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Weight and Mass Converter: Convert Kilograms, Pounds, Ounces, Grams and Tons

Converting kilograms to pounds, pounds to kilograms, grams to ounces, or tons to pounds is something people do every day. The calculation itself is usually simple, but remembering the correct conversion factor can be surprisingly difficult, especially when several different measurement systems are involved.

The CalculatorKits Weight and Mass Converter makes these conversions quick and straightforward. Enter your value, select the unit you have, choose the unit you need, and the converted result appears instantly.

For example:

1 kilogram = 2.20462 pounds

So:

10 kilograms = 22.0462 pounds

The converter supports 12 weight and mass units, including kilograms, pounds, ounces, grams, metric tons, stones, and other commonly used units. It uses the kilogram as its base unit and performs the calculation directly in your browser.

Use the CalculatorKits Weight and Mass Converter

What Is a Weight and Mass Converter?

A weight and mass converter changes a measurement from one unit to another while preserving the same quantity.

For example, a package might be listed as 5 kilograms in one country and 11.0231 pounds in another. The package has not become heavier or lighter. Only the unit used to describe its mass has changed.

Common conversions include:

1. Kilograms to pounds
2. Pounds to kilograms
3. Grams to ounces
4. Ounces to grams
5. Kilograms to stones
6. Metric tons to kilograms
7. Metric tons to pounds
8. Grams to kilograms
9. Pounds to ounces
10. Carats to grams

Technically, mass and weight are not the same physical quantity. Mass describes the amount of matter in an object, while weight is a force caused by gravity. The kilogram is the SI base unit of mass. BIPM also distinguishes weight as a force rather than mass.

In everyday conversation, however, people commonly use the word “weight” when they mean mass. That is why online tools often use the familiar phrase weight and mass converter.

How to Use the CalculatorKits Weight and Mass Converter

The CalculatorKits tool uses a simple From and To workflow.

Step 1: Enter your value

Open the Weight and Mass Converter and enter the number you want to convert.

For example:

10

Step 2: Select the original unit

Choose the unit your measurement is currently expressed in.

For example:

From: Kilograms

Step 3: Select the target unit

Choose the unit you want for the final answer.

For example:

To: Pounds

Step 4: Read the result

The converted value appears immediately.

For example:

10 kg = 22.0462 lb

You can then change the value or switch the units to perform another calculation.

The CalculatorKits converter uses the kilogram as its base unit and applies the appropriate conversion factor between the selected units.

What Is the Difference Between Mass and Weight?

This is an important concept, particularly for students, engineers, scientists, and anyone working with technical measurements.

Mass

Mass is a measure of the amount of matter in an object.

The SI unit of mass is the kilogram (kg). The modern definition of the kilogram is based on a fixed numerical value of the Planck constant.

Mass does not change simply because an object moves from Earth to another location.

For example, an object with a mass of:

10 kg

still has a mass of 10 kg on the Moon.

Weight

Weight is a force associated with gravity.

In simplified form:

Weight = Mass × Gravitational Acceleration

This means the weight of an object can change when the gravitational field changes, even though its mass remains the same.

For everyday shopping, cooking, shipping, fitness, and household measurements, people often use “weight” and “mass” interchangeably. For scientific calculations, it is important to keep the distinction clear.

Common Weight and Mass Units

Different industries and countries use different units.

Kilogram

The kilogram, written as kg, is the SI base unit of mass.

It is widely used around the world for people, products, luggage, shipping, science, engineering, and everyday measurements.

Important relationships include:

1 kg = 1,000 g

1 kg ≈ 2.20462 lb

1 kg ≈ 35.274 oz

Gram

The gram, written as g, is useful for smaller quantities.

1 gram = 0.001 kilogram

Therefore:

1 kg = 1,000 g

Grams are commonly used for food ingredients, small products, laboratory measurements, jewelry, and many everyday items.

Milligram

The milligram, written as mg, is much smaller than a gram.

1 g = 1,000 mg

Therefore:

1 kg = 1,000,000 mg

Milligrams are commonly encountered in scientific, pharmaceutical, nutritional, and laboratory contexts.

Pound

The pound, written as lb, is widely used in the United States and is also used in several other countries.

The standard avoirdupois pound is approximately:

0.4535924 kg

Therefore:

1 kg ≈ 2.20462 lb

NIST lists the international pound conversion as approximately 0.4535924 kilograms.

Ounce

The ordinary avoirdupois ounce, written as oz, is commonly used for smaller weights in the US and UK systems.

1 pound = 16 ounces

One avoirdupois ounce is approximately:

28.3495 grams

Be careful with the word ounce because a troy ounce used for precious metals is different from an ordinary avoirdupois ounce. NIST lists different conversion factors for these units.

Metric Ton

A metric ton, also called a tonne, is written as t.

1 metric ton = 1,000 kg

Therefore:

1 metric ton = 2,204.62 pounds

Metric tons are commonly used for shipping, manufacturing, industrial materials, agriculture, and large quantities of products.

Stone

The stone, written as st, is traditionally used in the United Kingdom and is especially familiar for expressing human body weight.

1 stone = 14 pounds

One stone is approximately:

6.35029 kg

For example:

10 stone = 140 pounds

which is approximately:

63.5029 kg

Carat

The carat, written as ct, is commonly used for gemstones.

1 carat = 0.2 grams

Therefore:

5 carats = 1 gram

A gemstone’s carat weight describes mass. It should not be confused with the term “karat,” which describes gold purity.

Weight and Mass Conversion Table

Here are some of the most useful relationships:

Conversion	Equivalent
1 kg to grams	1,000 g
1 kg to pounds	2.20462 lb
1 kg to ounces	35.274 oz
1 pound to kilograms	0.453592 kg
1 pound to ounces	16 oz
1 ounce to grams	28.3495 g
1 gram to ounces	0.035274 oz
1 metric ton to kilograms	1,000 kg
1 metric ton to pounds	2,204.62 lb
1 stone to pounds	14 lb
1 stone to kilograms	6.35029 kg
1 carat to grams	0.2 g

These relationships are based on standardized unit definitions and conversion factors. NIST provides detailed conversion factors for pounds, ounces, metric tons, stones and other mass units.

How Weight and Mass Conversion Works

CalculatorKits uses the kilogram as the base unit for its weight and mass conversions.

The general formula is:

Result = (Input × From Factor) ÷ To Factor

The converter first relates the original value to kilograms and then converts the kilogram value into the target unit.

For example, to convert 1 kilogram to pounds:

1 kg × 2.20462 = 2.20462 lb

Therefore:

1 kg = 2.20462 pounds

The same basic process works in reverse.

To convert 10 pounds to kilograms:

10 × 0.453592 = 4.53592 kg

Therefore:

10 pounds ≈ 4.53592 kilograms

The calculator performs these steps automatically.

Kilograms to Pounds

Kilograms to pounds is one of the most common weight conversions.

The formula is:

Pounds = Kilograms × 2.20462

For example:

5 kg × 2.20462 = 11.0231 lb

Therefore:

5 kilograms = 11.0231 pounds

For everyday purposes, this might be rounded to:

11.02 pounds

Pounds to Kilograms

To convert pounds to kilograms:

Kilograms = Pounds × 0.453592

For example:

20 lb × 0.453592 = 9.07184 kg

Therefore:

20 pounds ≈ 9.07 kilograms

This conversion is useful when reading US product specifications, luggage limits, fitness information, or shipping information and you need the value in kilograms.

Grams to Ounces

To convert grams to ordinary avoirdupois ounces:

Ounces = Grams ÷ 28.3495

For example:

100 g ÷ 28.3495 ≈ 3.5274 oz

Therefore:

100 grams ≈ 3.5274 ounces

For cooking or everyday use, you might round that to:

3.53 ounces

Ounces to Grams

For the reverse conversion:

Grams = Ounces × 28.3495

For example:

8 oz × 28.3495 = 226.796 g

Therefore:

8 ounces ≈ 226.8 grams

This can be useful when converting food packaging or recipes between measurement systems.

Kilograms to Stones

To convert kilograms to stones, divide by approximately 6.35029.

For example:

70 kg ÷ 6.35029 ≈ 11.0231 stone

Therefore:

70 kg ≈ 11.02 stone

Because a stone is traditionally divided into 14 pounds, body weight may also be expressed as a combination of stones and pounds.

For example, approximately 70 kg is around:

11 stone 0.3 pounds

when expressed in the traditional format.

Metric Tons to Pounds

Large quantities are often measured in metric tons.

The relationship is:

1 metric ton = 1,000 kg

Since:

1 kg ≈ 2.20462 lb

one metric ton is:

1,000 × 2.20462 = 2,204.62 lb

Therefore:

1 metric ton ≈ 2,204.62 pounds

This conversion is particularly useful in manufacturing, shipping, agriculture, construction, and industrial supply.

Metric Ton vs Short Ton vs Long Ton

The word “ton” can be confusing because different systems use different definitions.

A metric ton, or tonne, is:

1,000 kg

A US short ton is:

2,000 pounds

which is approximately:

907.1847 kg

A UK long ton is:

2,240 pounds

which is approximately:

1,016.047 kg

NIST lists these as distinct units with different conversion factors.

This is important when dealing with shipping documents, industrial specifications, commodities, or international trade.

Never assume that “ton” automatically means 1,000 kilograms.

Weight and Mass Conversion for Cooking

Cooking is a common reason for converting grams, kilograms, ounces, and pounds.

For example:

500 g ≈ 17.637 oz

and:

1 lb ≈ 453.592 g

A recipe written in grams can therefore be converted into ounces when needed.

However, weight based measurements are generally more precise than volume based approximations for many cooking applications. If a recipe provides a weight measurement, it is usually best to preserve that measurement rather than converting it into cups or tablespoons unless necessary.

Also remember that an ounce by weight is not the same thing as a fluid ounce. The former measures mass, while the latter measures volume.

Weight and Mass Conversion for Shipping

Shipping companies frequently use kilograms and pounds for package weights.

For example:

25 kg × 2.20462 = 55.1155 lb

So:

25 kg ≈ 55.12 pounds

This can help when comparing international shipping limits.

However, shipping providers may use their own rules for rounding, dimensional weight, or billable weight. A simple unit conversion does not determine the final shipping charge.

Weight and Mass Conversion for Fitness

Body weight is commonly expressed in kilograms in many countries and pounds in the United States.

For example:

70 kg ≈ 154.32 lb

while:

180 lb ≈ 81.65 kg

A converter makes it easy to compare measurements without repeatedly calculating the conversion manually.

Keep in mind that body weight is affected by normal day to day variation, and a converted value is simply the same measurement expressed in another unit.

Weight and Mass Conversion for Jewelry

Jewelry introduces another important distinction because precious metals and gemstones can use different units.

A gemstone’s mass may be expressed in carats:

1 carat = 0.2 grams

Precious metals are commonly traded using troy ounces, which are different from ordinary avoirdupois ounces.

One troy ounce is approximately:

31.1035 grams

while one ordinary avoirdupois ounce is approximately:

28.3495 grams

Using the wrong ounce can therefore produce a meaningful error.

Common Weight and Mass Conversion Mistakes

Confusing kilograms and pounds

Remember:

1 kg ≈ 2.20462 lb

A kilogram is heavier than a pound, so converting kilograms to pounds produces a larger numerical value.

Confusing ounces by mass with fluid ounces

An ordinary ounce measures mass.

A fluid ounce measures volume.

They cannot be treated as interchangeable.

Assuming every ton is the same

Metric tons, short tons, and long tons have different definitions.

Always identify which ton is being used.

Confusing mass and weight

Mass is measured in kilograms.

Weight is a force.

In everyday conversation, “weight” often means mass, but the distinction matters in physics and engineering.

Using a troy ounce as an ordinary ounce

Precious metals use troy ounces in many contexts.

A troy ounce is heavier than an ordinary avoirdupois ounce.

Rounding too early

Suppose you convert kilograms to pounds and then use that rounded result in another calculation. The final result may contain additional rounding error.

For greater accuracy, retain the converter’s full result until the final calculation.

How Accurate Is the Weight and Mass Converter?

The CalculatorKits Weight and Mass Converter uses standardized conversion constants and the kilogram as its base unit. The tool states that calculations are performed locally in the browser and that rounding is applied at the final display stage.

For common conversions such as kilograms to pounds, grams to ounces, and metric tons to kilograms, these standardized relationships provide the precision needed for everyday, educational, commercial, and many professional applications.

NIST publishes the corresponding conversion factors for standard mass units, including the international pound, ounce, metric ton, short ton, and long ton.

For legal, certified, laboratory, medical, or safety critical measurements, follow the applicable measurement standards and use properly calibrated equipment where required.

Why the Kilogram Is the Base Unit

The kilogram has a special position in the SI system because it is the SI base unit of mass.

The modern SI definition of the kilogram is based on the exact numerical value assigned to the Planck constant. This replaced the previous artifact based definition in 2019.

For ordinary conversions, you do not need to know the details of the definition. What matters is that the kilogram provides a standardized reference for expressing mass.

That makes it convenient as the base unit for a converter.

Privacy and Browser Based Calculations

The CalculatorKits Weight and Mass Converter performs its calculations locally in the browser. The tool does not require an account to perform conversions and states that conversion calculations are not uploaded or stored remotely.

This makes it convenient for quick calculations on phones, tablets, and computers.

You can also perform repeated conversions without manually searching for conversion factors each time.

Related CalculatorKits Tools

Weight and mass calculations are often connected with other types of measurements. These four CalculatorKits tools can be useful depending on your task.

Volume Converter converts liters, gallons, milliliters, cubic meters, quarts, cups, and other volume units. It is useful when you need to compare the volume of a material with its mass.

Length Converter converts meters, feet, inches, kilometers, miles, centimeters, and other length units. It can help when dimensions or distances are part of a larger measurement problem.

Area Converter converts square meters, square feet, acres, hectares, and other area units. It is useful when mass is being considered in relation to a surface area.

Energy Converter converts joules, kilojoules, kilowatt hours, calories, BTU, and other energy units for calculations where mass and energy are related.

Frequently Asked Questions

How many pounds are in one kilogram?

One kilogram equals approximately 2.20462 pounds.

How many kilograms are in one pound?

One pound equals approximately 0.453592 kilograms.

How many grams are in one kilogram?

There are exactly:

1,000 grams in 1 kilogram

How many ounces are in one pound?

There are:

16 ordinary avoirdupois ounces in 1 pound

How many grams are in one ounce?

One ordinary avoirdupois ounce equals approximately:

28.3495 grams

How many kilograms are in a metric ton?

One metric ton equals:

1,000 kilograms

How many pounds are in a metric ton?

One metric ton equals approximately:

2,204.62 pounds

How many pounds are in a stone?

One stone equals:

14 pounds

How many kilograms are in a stone?

One stone is approximately:

6.35029 kilograms

What is the difference between mass and weight?

Mass describes the amount of matter in an object and is measured in kilograms in the SI system. Weight is a force resulting from gravity acting on that mass. In everyday language, the terms are often used interchangeably, but they have different meanings in physics.

Is a pound a unit of mass or weight?

The pound can be encountered in everyday contexts where people describe “weight,” but the exact physical quantity depends on how the term is being used. The avoirdupois pound is commonly used as a unit of mass in unit conversion tables. For technical work, always identify the quantity and unit definition being used.

Is a troy ounce the same as a regular ounce?

No. A troy ounce is approximately 31.1035 grams, while an ordinary avoirdupois ounce is approximately 28.3495 grams.

Can I convert kilograms to pounds without a calculator?

Yes. Multiply kilograms by approximately 2.20462.

For example:

20 × 2.20462 = 44.0924 pounds

For quick or repeated conversions, an online converter is less likely to lead to arithmetic or factor errors.

Can I convert pounds to kilograms?

Yes. Multiply pounds by approximately 0.453592.

For example:

50 × 0.453592 = 22.6796 kilograms

Should I round my conversion result?

Round according to the purpose of the measurement. A household estimate may only require two decimal places, while scientific or engineering work may require more precision.

Key Takeaways

Weight and mass conversion allows the same quantity to be expressed using different measurement units.

The most useful relationships to remember are:

1 kg = 1,000 g

1 kg ≈ 2.20462 lb

1 lb ≈ 0.453592 kg

1 lb = 16 oz

1 oz ≈ 28.3495 g

1 metric ton = 1,000 kg

1 metric ton ≈ 2,204.62 lb

1 stone = 14 lb

1 stone ≈ 6.35029 kg

1 carat = 0.2 g

The most important thing is to identify the exact unit before converting. Pounds, ounces, stones, metric tons, short tons, long tons, and troy ounces are not interchangeable.

For everyday calculations, the CalculatorKits Weight and Mass Converter handles the conversion automatically. Enter the value, select the From unit, choose the To unit, and use the displayed result.

For certified, legal, laboratory, medical, or safety critical measurements, always verify the result against the appropriate standard or calibrated measuring equipment.

References

1. BIPM, SI Base Unit: Kilogram
2. BIPM, The International System of Units
3. NIST, Guide to the SI, Appendix B: Conversion Factors
4. NIST, Guide to the SI, Appendix B.9: Factors for Units by Quantity
5. Encyclopaedia Britannica, Mass

• Written and reviewed by the CalculatorKits Editorial Team
• Last Updated: September 10, 2026