Calorie Calculator
Estimate your daily calorie needs using the Mifflin-St Jeor equation. Get personalized recommendations for weight loss, maintenance, or muscle gain.
How Calories Are Calculated
Mifflin-St Jeor Equation:
Male: BMR = (4.536 × Weight) + (15.88 × Height) − (5 × Age) + 5
Female: BMR = (4.536 × Weight) + (15.88 × Height) − (5 × Age) − 161
Weight in lbs · Height in inches · Age in years
TDEE = BMR × Activity Factor
Your Calorie Results
Analysis completeBMR Level
Your Details
What This Means
Your TDEE is the number of calories you burn daily. Use the goal cards above to plan your nutrition for weight loss, maintenance, or muscle gain.
Calorie Comparison
Suggested Macronutrient Breakdown
Estimated Progress
≈ Stable weight
≈ 0.25–0.5 kg/week
≈ 0.25–0.5 kg/week
Suggested Meal Distribution
Activity Equivalents (≈300 kcal)
Estimated Goal Timeline
Healthy Eating Tips
- 🥗 Prioritize whole foods
- 🥩 Eat adequate protein
- 🥦 Include vegetables and fruits
- 💧 Stay hydrated
- 🚫 Limit ultra-processed foods
Calculation Method
Daily calorie needs estimated by applying your selected activity level to BMR.
Macronutrients based on general guidelines (Protein 30%, Carbs 40%, Fat 30%).
Personal Factors
How This Calculator Works
Basal Metabolic Rate (BMR) is the number of calories your body burns at rest to maintain vital functions like breathing, circulation, and cell repair.
Mifflin-St Jeor Equation (1990):
Male: BMR = (4.536 × Weight) + (15.88 × Height) − (5 × Age) + 5
Female: BMR = (4.536 × Weight) + (15.88 × Height) − (5 × Age) − 161
Total Daily Energy Expenditure (TDEE):
TDEE = BMR × Activity Factor
Activity Factors:
• Sedentary: 1.2
• Lightly Active: 1.375
• Moderately Active: 1.55
• Very Active: 1.725
• Extra Active: 1.9
Real Examples
Limitations
- • Calorie estimates are approximations, not exact measurements
- • Individual metabolism varies based on genetics and body composition
- • These formulas may not apply to athletes or those with high muscle mass
- • Always consult a healthcare professional for personalized nutrition advice
References
Educational information based on established nutrition research.
- Mifflin MD, et al. – A new predictive equation for resting energy expenditure (1990)
- Academy of Nutrition and Dietetics – Calorie Guidelines
- American College of Sports Medicine (ACSM) – Exercise Guidelines
References were selected from recognized nutrition and health sources and are reviewed periodically for accuracy.
Trust & Privacy
All calculations are performed locally in your browser. No personal information is stored or shared.
Editorial Process
The CalculatorKits editorial team reviews this tool periodically for:
- • Formula accuracy
- • Nutrition references
- • Educational content
- • User guidance
Last reviewed: July 2026
Frequently Asked Questions
TDEE (Total Daily Energy Expenditure) is the total number of calories you burn each day, including all activities. It's the key number for weight management.
It's a widely validated formula for estimating BMR based on age, gender, weight, and height. It's considered one of the most accurate equations.
This calculator provides estimates. Individual metabolism varies based on genetics, muscle mass, and other factors. Use as a starting point for nutrition planning.
No. This is an educational tool for general awareness. It should not replace professional medical or nutrition advice.
Recalculate when your weight changes significantly (5+ lbs), your activity level changes, or every 4-6 weeks to adjust your nutrition plan.
📍 © 2026 CalculatorKits — Calorie Calculator · For educational use only
Calorie Calculator: Estimate Your Daily Calorie Needs
Introduction
Knowing how much energy you need each day can make nutrition decisions much easier. Whether you want to maintain your current weight, work toward weight loss, or support weight gain, having a reasonable estimate gives you a useful starting point.
The CalculatorKits Calorie Calculator uses the Mifflin St Jeor equation to estimate resting energy expenditure. CalculatorKits may label this value as BMR in the calculator interface. The original Mifflin St Jeor research described the equation as a prediction of resting energy expenditure rather than a direct measurement of metabolism.
The calculator then applies an activity factor to estimate your total daily energy expenditure, commonly called TDEE.
You only need to enter your gender, age, weight, height, and activity level. The calculation is quick, but the result should be understood as an estimate rather than an exact measurement of what your body burns every day.
Your actual energy needs can vary because of body composition, physical activity, everyday movement, age, genetics, medications, health conditions, and other factors.
This guide explains how the CalculatorKits tool works, how to enter your information correctly, how to understand the result, and how to use the estimate responsibly.
Quick Answer
A Calorie Calculator estimates your daily energy requirement using information such as age, gender, weight, height, and physical activity.
CalculatorKits first estimates resting energy expenditure with the Mifflin St Jeor equation. It then multiplies that estimate by a selected activity factor to produce an estimated daily energy requirement.
In simple terms:
Resting energy estimate × Activity factor = Estimated TDEE
The result can provide a useful starting point for understanding your approximate maintenance calorie needs.
It can also help you think about calorie intake when your goal is weight loss or weight gain. However, the calculator does not determine the appropriate calorie deficit or surplus for a particular person.
Important: Who Should Use This Calculator?
The CalculatorKits tool is intended for general adult estimates.
It is not designed to determine calorie requirements for children, teenagers, pregnancy, breastfeeding, or people with condition specific nutritional requirements.
If your nutritional needs are affected by a medical condition, medication, pregnancy, breastfeeding, or another special circumstance, a qualified healthcare professional can provide guidance based on your individual situation.
The National Institute of Diabetes and Digestive and Kidney Diseases states that its Body Weight Planner is intended for adults and is not intended for people under 18 or for pregnant or breastfeeding women.
How Many Calories Do I Need Per Day?
There is no single calorie number that is appropriate for everyone.
Your daily energy needs depend on your age, height, weight, body composition, activity, and many other factors. Even two people with the same height and weight can have different energy requirements because their body composition and daily routines may differ.
The CalculatorKits estimate can give you a useful baseline.
| Goal | What the calculator provides |
|---|---|
| Maintain weight | An estimated maintenance calorie baseline |
| Lose weight | An estimated baseline for discussing or planning calorie intake |
| Gain weight | An estimated baseline for planning a suitable calorie increase |
The important point is that the calculator provides the baseline. It does not decide what your personal calorie target should be.
For weight management, food intake and physical activity both matter. Sleep, stress, medications, medical conditions, age, genetics, and other circumstances can also affect weight management.
What Is a Calorie Calculator?
A Calorie Calculator is an online tool that estimates how much energy your body may need during a typical day.
The CalculatorKits tool uses five main pieces of information:
- Gender
- Age
- Weight
- Height
- Activity level
The calculation has two main parts.
First, the tool estimates resting energy expenditure using the Mifflin St Jeor equation.
Second, it applies an activity factor to estimate total daily energy expenditure.
This approach makes the tool useful for people who want a quick estimate without laboratory testing.
It is important to understand what the result represents. It is not a direct reading of your metabolism, and it does not measure every calorie your body uses during the day.
How Does the Calorie Calculator Work?
The CalculatorKits calculation follows a simple process.
Step 1: Estimate resting energy expenditure
The Mifflin St Jeor equation uses your age, gender, weight, and height to estimate resting energy expenditure.
Resting energy expenditure refers to the energy your body uses to support essential functions while at rest.
Your body needs energy even when you are not exercising. Breathing, circulation, maintaining body temperature, and other physiological processes require energy.
The original Mifflin St Jeor study was published in 1990 and developed a predictive equation using measured resting energy expenditure in healthy adults.
Step 2: Apply your activity factor
Your resting energy requirement is only one part of your total daily energy expenditure.
Walking, exercising, working, standing, household activities, commuting, and other movement add to the energy you use during the day.
CalculatorKits accounts for this by applying an activity factor based on the activity level you select.
Step 3: Return an estimated daily energy requirement
The calculator multiplies the resting energy estimate by your selected activity factor.
TDEE = Resting energy estimate × Activity factor
The result is an estimated amount of energy you may use during a typical day.
How We Calculate Your Daily Calorie Estimate
Here is the calculation in a simple three step format.
Step 1: Estimate resting energy expenditure using the Mifflin St Jeor equation.
Step 2: Apply the activity factor selected by the user.
Step 3: Return an estimated daily energy requirement.
This is a predictive calculation, not a direct measurement of metabolism.
For the imperial values displayed by the CalculatorKits tool, the equation is:
Male:
4.536 × weight in pounds + 15.88 × height in inches − 5 × age + 5
Female:
4.536 × weight in pounds + 15.88 × height in inches − 5 × age − 161
The commonly published metric form is:
Male:
10 × weight in kilograms + 6.25 × height in centimeters − 5 × age + 5
Female:
10 × weight in kilograms + 6.25 × height in centimeters − 5 × age − 161
The original research describes the equation as a prediction of resting energy expenditure. CalculatorKits may display this resting estimate as BMR because that terminology is familiar to many users.
The distinction is useful to understand.
REE is the research terminology for predicted resting energy expenditure.
BMR is a commonly used calculator label for a resting calorie estimate.
These concepts are closely related, but the Mifflin St Jeor equation should not be presented as a direct measurement of an individual’s metabolism.
Activity Levels Used by the Calculator
Your selected activity level affects the final daily estimate.
CalculatorKits uses the following activity factors:
| Activity Level | Activity Factor | Description |
|---|---|---|
| Sedentary | 1.2 | Little or no exercise, desk job |
| Lightly Active | 1.375 | Light exercise 1 to 3 days per week |
| Moderately Active | 1.55 | Moderate exercise 3 to 5 days per week |
| Very Active | 1.725 | Hard exercise 6 to 7 days per week |
| Extra Active | 1.9 | Athletic training or physically demanding work |
These categories are broad. Real life does not always fit perfectly into one activity level.
When choosing your activity category, think about your normal week rather than one particularly active day.
For example, someone who exercises three times a week but spends most of the rest of the day sitting may have a different overall activity pattern from someone who exercises three times a week and also walks several hours during work.
How to Use the Calorie Calculator
The CalculatorKits tool is designed to be simple. Follow these steps carefully.
1. Select your gender.
Choose Male or Female.
The Mifflin St Jeor equation uses different constants for these selections, so make sure the appropriate option is selected.
2. Enter your age
Enter your current age in years.
Use your current age rather than an age you will reach later in the year.
3. Enter your weight and check the unit
Enter your current weight and check the selected unit.
The CalculatorKits interface provides a unit selector for weight. Make sure the number you enter matches the selected unit.
For example, do not enter a kilogram value while the calculator is set to pounds.
4. Enter your height
Enter your height using the feet and inches fields shown in the calculator.
For example, if you are 5 feet 8 inches tall:
Feet: 5
Inches: 8
Do not enter your complete height in inches into the feet field.
5. Select your activity level
Choose the category that best represents your normal routine.
Sedentary: Little or no exercise and mostly sitting during the day.
Lightly Active: Light exercise around 1 to 3 days each week.
Moderately Active: Moderate exercise around 3 to 5 days each week.
Very Active: Hard exercise around 6 to 7 days each week.
Extra Active: Athletic training or a physically demanding job and lifestyle.
Try to be realistic rather than automatically choosing the highest category.
6. Check your information
Before calculating, review your gender, age, weight, units, height, and activity level.
A quick check can prevent simple input mistakes from affecting the result.
7. Click Calculate Calories
Once your information looks correct, click Calculate Calories.
The calculator will process your information and display your estimated daily calorie requirement.
8. Review your result
Use the displayed number as an estimate of your daily energy needs.
It is not a laboratory measurement and should not be interpreted as an exact number that your body must use every day.
9. Use Try Example or Reset if needed
You can select Try Example if you want to see the calculator in action.
Use Reset when you want to clear the current information and start again.
Understanding Your Result
The number produced by the Calorie Calculator becomes easier to understand when you know the difference between resting energy and total daily energy expenditure.
Resting energy expenditure
Resting energy expenditure is an estimate of the energy your body uses while at rest.
It covers energy required for essential physiological functions.
The Mifflin St Jeor equation predicts this value using your age, gender, weight, and height.
TDEE
TDEE stands for Total Daily Energy Expenditure.
It is an estimate of your total energy use during a normal day after activity is taken into account.
This is why TDEE is generally more useful than resting energy alone when you are trying to understand your daily calorie requirements.
A person may have a resting energy estimate of around 1,500 calories but require considerably more energy over a full day because of walking, work, exercise, and other movement.
If you want to explore resting energy requirements separately, you can also use the BMR Calculator.
Using Your Calorie Estimate for Different Goals
Once you have an estimate, you may want to connect it with your personal goal.
Maintaining your weight
If your goal is weight maintenance, the estimated TDEE provides a useful starting point for understanding your approximate maintenance needs.
Your actual maintenance intake may be somewhat higher or lower.
Looking at longer term patterns can provide more useful information than focusing on one day.
If your weight remains reasonably stable over time while your activity and eating pattern are consistent, your average intake may be relatively close to your actual energy requirements.
Working toward weight loss
Weight loss generally occurs when energy intake remains below energy expenditure over time.
However, the calculator does not determine the appropriate calorie deficit for a particular person.
A suitable approach can depend on health status, nutritional needs, medications, activity, current weight, and other personal circumstances.
Healthy weight management is about more than calorie intake. The CDC recommends considering healthy eating patterns, physical activity, adequate sleep, and stress management as part of a broader approach to weight management.
Supporting weight gain
Someone trying to gain weight may need more energy than they currently use, depending on the goal.
If the goal is to support muscle gain, calorie intake is only one part of the picture. Resistance training, sufficient protein, overall nutrition, and recovery are also relevant.
The Macro Calculator can be used alongside your calorie estimate to explore macronutrient distribution.
Why Your Actual Calorie Needs May Differ
A predictive equation cannot know everything about your body or your daily routine.
Body composition is one reason.
Two people can have the same body weight while having different proportions of muscle and fat.
Daily movement is another.
One person might have a desk job and spend most of the day sitting. Another person might have a similar exercise routine but spend several hours walking or standing at work.
Exercise intensity and duration can also vary.
Other factors, including age, genetics, medications, medical conditions, sleep, and lifestyle, can affect weight management and energy requirements.
This does not make the calculator useless.
It simply means the result should be treated as a starting estimate rather than a guaranteed personal requirement.
Why Two Calorie Calculators Can Give Different Results
It is normal to find different calorie estimates on different websites.
Two calculators may use different equations, activity factors, assumptions, or methods for adjusting results.
Some calculators may also include additional adjustments for particular weight goals.
The Mifflin St Jeor equation is widely used and has performed well compared with several commonly used predictive equations. However, predictive equations can still have individual errors.
If two calculators give you different results, do not immediately assume that one is wrong.
Instead, check:
- Which equation does the calculator use?
- What measurements does it require?
- How does it define activity levels?
- Does it apply an additional goal adjustment?
- Does it explain that the result is an estimate?
Understanding the methodology is more useful than simply choosing whichever calculator gives you the number you prefer.
If you want another way to estimate total daily energy expenditure, you can also use the TDEE Calculator.
How Accurate Is a Calorie Calculator?
A Calorie Calculator can provide a useful estimate, but it cannot measure your exact daily energy expenditure.
The Mifflin St Jeor equation was developed using measured resting energy expenditure in healthy adults. Later research comparing predictive equations found Mifflin St Jeor to be among the more reliable commonly used equations, while also showing that individual prediction errors can occur.
That distinction matters.
An equation can perform well across a population while still being somewhat higher or lower for a particular person.
The activity factor introduces another source of uncertainty because daily activity is difficult to summarize with a single category.
People also change.
Your weight, activity, routine, and other circumstances may change over time, which can change your energy requirements.
The best way to think about the calculator is simple:
It provides a useful estimate, not a direct measurement.
Common Calorie Calculator Mistakes
Small input mistakes can make a large difference.
Using the wrong weight unit: Check the unit before entering your weight.
Entering height incorrectly: If the tool asks for feet and inches, enter them into the correct fields.
Choosing an activity level that is too high: Occasional workouts do not necessarily make an entire lifestyle very active.
Ignoring everyday movement: Consider walking, standing, physical work, household tasks, and commuting as part of your overall activity.
Expecting one exact number: Your energy expenditure naturally changes from day to day.
Reacting to a single scale reading: Short term changes in body weight can occur for many reasons and do not necessarily represent changes in body fat.
Assuming the calculator sets your diet: The result is an estimate and does not determine an appropriate diet or medical treatment plan.
Calorie Calculator vs BMR Calculator vs TDEE Calculator
These tools are related, but they answer slightly different questions.
BMR is about resting energy.
TDEE is about estimated total daily energy expenditure.
A BMR Calculator focuses on the estimated energy your body requires at rest.
A TDEE Calculator focuses on estimated total daily energy use after activity is considered.
The CalculatorKits calorie calculation starts with a resting energy estimate and then applies an activity factor to arrive at an estimated daily requirement.
If you want to explore total daily energy expenditure separately, you can use the TDEE Calculator.
Practical Tips for Using Your Calorie Estimate
A calculator result becomes more useful when you use it with realistic expectations.
Start with accurate information. Check your weight, height, age, and units before calculating.
Choose your activity level based on your normal lifestyle rather than your most active day.
Think about your overall routine. A workout is important, but it is only one part of physical activity.
It is also useful to look beyond calories.
The current Dietary Guidelines for Americans cover the 2025 to 2030 period and emphasize overall healthy dietary patterns and nutrient dense foods rather than treating calories as the only consideration.
Physical activity matters as well. Current US guidance recommends that adults get at least 150 minutes of moderate intensity aerobic activity each week or 75 minutes of vigorous activity, along with muscle strengthening activity on at least two days each week.
You do not need to make every day identical.
A practical routine can include different calorie amounts on different days while still maintaining a consistent overall eating pattern.
Is This Calorie Calculator Suitable for Everyone?
The calculator is intended for general adult estimates.
It is not a replacement for individualized nutrition assessment.
People who are pregnant or breastfeeding, children and teenagers, and people with medical conditions that affect nutrition or metabolism may need different considerations.
The same applies to people with highly specialized nutritional requirements or situations where food intake needs to be medically managed.
The NIDDK Body Weight Planner similarly limits its intended use to adults and states that it is not intended for younger people or pregnant or breastfeeding women.
If you have questions about your individual calorie needs because of a medical condition, medication, pregnancy, breastfeeding, or another special circumstance, speak with a qualified healthcare professional.
Privacy and Calculator Use
The CalculatorKits calculator is designed to provide an estimate without requiring an account.
The current calculator interface states that calculations are performed locally in the browser and that personal information is not stored or shared.
The calculator also provides an instant result without requiring users to create a profile.
Only enter the information needed to use the calculator.
Frequently Asked Questions
What is a Calorie Calculator?
A Calorie Calculator estimates your daily energy needs using information such as age, gender, weight, height, and activity level. CalculatorKits uses the Mifflin St Jeor equation and an activity factor.
How many calories do I need per day?
Your daily calorie needs depend on factors such as age, height, weight, body composition, activity, and individual circumstances. The calculator provides an estimate that can serve as a starting point.
What is resting energy expenditure?
Resting energy expenditure is the energy your body is estimated to use while at rest for essential physiological functions. The Mifflin St Jeor equation predicts resting energy expenditure from basic personal measurements.
Is BMR the same as resting energy expenditure?
The terms are closely related, but they are not measurements of the same thing. The original Mifflin St Jeor research describes its equation as a prediction of resting energy expenditure. Consumer calculators often use BMR as a familiar label for a resting calorie estimate.
What is TDEE?
TDEE means Total Daily Energy Expenditure. It is an estimate of the total energy your body uses during a normal day after physical activity is taken into account.
Is the Mifflin St Jeor equation accurate?
It is a well established predictive equation and has performed well among commonly used equations. However, it still produces an estimate, and individual results can differ from measured energy expenditure.
Why does my result differ from another calculator?
Different calculators can use different equations, activity factors, assumptions, and goal adjustments. Compare the methodology rather than focusing only on the final number.
Which activity level should I choose?
Choose the level that best represents your normal lifestyle. Consider exercise as well as walking, standing, work, commuting, and other daily movement.
Can I use the Calorie Calculator for weight loss?
Yes, it can provide a useful estimate of your daily energy needs. However, it does not determine the appropriate calorie deficit for a particular person.
Can I use the Calorie Calculator for muscle gain?
It can help estimate your daily energy requirement. Muscle gain also involves appropriate resistance training, adequate nutrition, sufficient protein, and recovery.
Should I use my BMR as my daily calorie target?
BMR represents resting energy rather than your complete daily energy expenditure. Your estimated TDEE is generally more relevant when considering your normal daily energy needs.
How often should I recalculate my calorie needs?
There is no universal schedule. Recalculate when important factors such as your body weight or activity level change rather than reacting to small daily fluctuations.
Is this calculator a medical tool?
No. It is an educational estimation tool. It does not diagnose medical conditions, prescribe treatment, or replace individualized nutrition advice from a qualified healthcare professional.
Key Takeaways
The CalculatorKits Calorie Calculator provides an estimate of your daily energy needs using the Mifflin St Jeor equation and an activity factor.
The Mifflin St Jeor equation predicts resting energy expenditure. CalculatorKits may label this value as BMR in the calculator interface.
The calculation then uses your selected activity level to estimate TDEE.
For the most useful result, enter your age, weight, height, units, gender, and activity level carefully.
Your result is a starting estimate, not a direct measurement of your metabolism.
Actual energy needs vary between people and can change over time.
Use the estimate as one piece of information rather than treating it as an exact dietary prescription.
Related CalculatorKits Tools
BMR Calculator
Explore your estimated resting energy requirement.
TDEE Calculator
Estimate your total daily energy expenditure.
Macro Calculator
Explore estimated protein, carbohydrate, and fat distribution.
BMI Calculator
Calculate BMI using your height and weight.
References
- Mifflin et al., A New Predictive Equation for Resting Energy Expenditure in Healthy Individuals
- Frankenfield et al., Comparison of Predictive Equations for Resting Metabolic Rate
- National Institute of Diabetes and Digestive and Kidney Diseases, Body Weight Planner
- Centers for Disease Control and Prevention, Steps for Losing Weight
- Centers for Disease Control and Prevention, Physical Activity and Your Weight and Health
- Centers for Disease Control and Prevention, Tips for Maintaining a Healthy Weight
- Dietary Guidelines for Americans, 2025 to 2030
- Physical Activity Guidelines for Americans
Medical Disclaimer
This calculator and the information in this article are provided for general knowledge and educational purposes only. The results are estimates and should not be considered medical or professional health advice. For personalized nutrition or health guidance, please consult a qualified healthcare professional.
Written and reviewed by the CalculatorKits Editorial Team
Last Updated: September 3, 2026