Mass Calculator

Need to quickly convert 5 kilograms to pounds, or figure out the mass of a steel beam given its volume and density? A mass calculator simplifies these tasks by providing instant, accurate results without manual math.

What Is Mass?

Mass is a measure of how much matter an object contains. Unlike weight, which depends on gravity, mass remains constant regardless of location. The kilogram (kg) serves as the base SI unit, but everyday life uses many other units: grams (g), pounds (lb), ounces (oz), stones (st), and tons.

How Do You Convert Between Mass Units?

Converting between mass units involves multiplying by a fixed conversion factor. Our mass calculator eliminates the hassle by doing the math for you. Enter a value, pick the starting unit, choose the target unit, and the result appears instantly.

Here are some common conversion factors used by the tool:

  • 1 kg = 1,000 g = 2.20462 lb
  • 1 lb = 16 oz = 0.453592 kg
  • 1 stone = 14 lb = 6.35029 kg
  • 1 metric ton (tonne) = 1,000 kg ≈ 2,204.62 lb
  • 1 short ton (US) = 2,000 lb ≈ 907.185 kg
  • 1 long ton (UK) = 2,240 lb ≈ 1,016.05 kg
Calculator Mode
Mass Unit Converter
Common Conversion Factors
UnitAbbreviationEquals 1 kg
Milligrammg1,000,000
Gramg1,000
Kilogramkg1
Metric tont0.001
Ounceoz35.274
Poundlb2.20462
Stonest0.157473
Short ton (US)ton0.00110231
Long ton (UK)ton0.000984207
Caratct5,000
Graingr15,432.4

Disclaimer: This calculator treats pounds and kilograms as units of mass. For precise weight (force) calculations, consult a dedicated weight calculator.

If you type 150 lb and select “pounds” → “kilograms,” the calculator above displays about 68.04 kg, applying the 0.453592 factor automatically. It handles 10+ units across metric and imperial systems, covering everything from milligrams to tons.

How to Calculate Mass from Density and Volume?

The calculator also works as a density‑based mass tool. When you know an object’s density and volume, use the formula:

m = ρ × V

where ρ (rho) is density in kg/m³, V is volume in m³, and m is mass in kg.

Example: A concrete block has a volume of 0.5 m³ and a density of 2,400 kg/m³. Its mass is 2,400 × 0.5 = 1,200 kg. Enter those numbers into the density mode of the mass calculator to verify the result instantly.

Disclaimer: This calculator treats pounds and kilograms as units of mass. For precise weight (force) calculations, consult a dedicated weight calculator.

Frequently Asked Questions

How do you convert kilograms to pounds?
Multiply the number of kilograms by 2.20462 to get pounds. For example, 10 kg × 2.20462 = 22.05 lb. Our mass calculator above applies this conversion automatically when you enter a value and select the units.
What is the formula for mass from density and volume?
Mass equals density multiplied by volume (m = ρ × V). If you know the density of a substance in kg/m³ and its volume in m³, multiply them to get mass in kilograms. The calculator can do this instantly if you switch to density mode.
How many grams are in a kilogram?
One kilogram equals 1,000 grams. The prefix “kilo” means 1,000, so 1 kg = 1,000 g. To convert kilograms to grams, multiply by 1,000. Our mass calculator handles this conversion seamlessly.
How many pounds are in a stone?
One stone equals 14 pounds. This unit is commonly used in the UK and Ireland for body weight. So a person weighing 10 stone has a mass of 140 pounds. The calculator includes stones and allows conversion to other units.
What is the difference between mass and weight?
Mass is the amount of matter in an object, measured in kilograms or slugs. Weight is the force exerted by gravity on that mass, measured in newtons or pounds-force. On Earth, the distinction is often ignored, but for scientific calculations, they are not interchangeable. This calculator deals with mass, not weight.
Can I convert metric tons to short tons with this calculator?
Yes, the mass calculator supports metric tons (tonnes), short tons (US tons) and long tons (UK tons). Enter the value in metric tons, select “metric ton” as the input unit and “short ton” as the output unit, and the conversion is done automatically.
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