Free · Volume and weight converters ⚖️

Mass, Customary Measures and Particle Equivalents

Convert mass between SI units, avoirdupois, troy, conventional celestial scales and particle mass equivalents.

  • Formula & worked example
  • Private in your browser
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Calculator inputs

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How to use this calculator

  1. Enter the known values in the units shown. Results update as you type.
  2. Where results are editable, change one to solve backwards. Lock a value to hold it fixed.
  3. Use the worked example to check the method. Reset restores the starting fields.

Private by default

Inputs and results stay in this browser tab. Bookify does not upload or store the values you enter.

Formula and method

1 avoirdupois pound equals exactly 0.45359237 kg, 453.59237 g and 16 avoirdupois ounces.

1 lb = 0.45359237 kg; 1 avoirdupois ounce = 1/16 lb; 1 troy ounce = 480 grains.

Worked example

Enter these known values and leave the other values blank.

Weight in pounds
1 lb
Weight in milligrams
453592 mg
Weight in grams
453.6 g
Weight in kilograms
0.453592 kg
Weight in other metric units
0.0004536 t
Weight in ounces
16 oz
Weight in stones
0.07143 st
Weight in other imperial units
0.0005 US ton
Weight in atomic mass units (amu)
2.73159709692956809783700756e+26 u
Weight in troy ounces
14.583 oz t
Weight in weights of Earth
7.595e-26 Earths
Weights in other units
2.2805e-31 Suns

Assumptions and limitations

  • This converts mass, not weight as a force. Avoirdupois and troy ounces have different definitions.
  • Atomic, electron, proton and neutron units use CODATA 2022 central values and have measured uncertainty. Earth (5.9722e24 kg) and solar (1.989e30 kg) masses are explicitly retained conventional approximate scales, not exact physical constants.
  • Clear the value you want to solve before entering the remaining independent measurements. Display rounding does not describe measurement uncertainty.

Common questions

How should I enter an unknown quantity?

Leave the unknown field empty. Supply enough independent values; lock a known value if you need to preserve it while changing another control.

References

Replace rounded captured unit factors with exact definitions or explicitly identified CODATA 2022 central values; preserve all choices and original captures.

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