Weight Calculator

Convert weight between all units, find your ideal weight, see how much you weigh on other planets, and compare your weight to everyday objects.

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Weight & Mass Unit Converter

Enter any weight value, select its unit, and instantly see the equivalent in all other units. Results update as you type.

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Weight on Other Planets

Your mass stays the same everywhere, but your weight changes with gravity. Enter your weight on Earth to see how much you would weigh on every planet, moon, and star.

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Ideal Body Weight Calculator

Calculate your ideal body weight using 4 established medical formulas: Robinson, Miller, Devine, and Hamwi. Enter your height and gender.

e.g. 175 cm = 5 ft 9 in
Compare your current vs ideal weight
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Weight Comparison

Enter a weight to see how it compares to familiar everyday objects and creatures. Gives a fun intuitive sense of scale.

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Weight & Mass Guide
Weight vs Mass — Key Difference
Mass is the amount of matter in an object — constant everywhere in the universe (measured in kg, g, lb).
Weight is the gravitational force on a mass — changes depending on gravity (measured in Newtons, N).

In everyday language, "weight" is used to mean mass. A 70 kg person has a mass of 70 kg, but their weight (force) on Earth is 686 N. On the Moon it would be 113 N — but their mass stays 70 kg.
Common Weight Unit Conversions
1 kg = 2.20462 lb = 35.27396 oz = 0.157473 stone
1 lb = 453.592 g = 16 oz = 0.0714286 stone
1 stone = 14 lb = 6.35029 kg
1 metric ton = 1,000 kg = 2,204.62 lb
1 US short ton = 2,000 lb = 907.185 kg
1 UK long ton = 2,240 lb = 1,016.05 kg
1 oz = 28.3495 g  |  1 carat = 0.2 g
1 grain = 0.0648 g  |  1 atomic mass unit = 1.6605 × 10²&sup7; kg
Interesting Weight Facts
Milky Way Galaxy: ~1.15 × 10⁶⁷ kg (including dark matter)
Sun: 1.989 × 10³⁰ kg (333,000 × Earth)
Earth: 5.972 × 10²⁴ kg
Moon: 7.342 × 10²² kg (1.2% of Earth)
Blue whale: ~150,000 kg (150 metric tons)
African elephant: ~6,000 kg
Human (avg adult): ~62 kg
US nickel coin: 5 g
Proton: 1.673 × 10⁻²⁷ kg
Electron: 9.109 × 10⁻³¹ kg
Ideal Weight Formulas
All formulas for adults over 5 feet (152 cm). H = height in inches above 60 inches.

Robinson (1983): Male = 52 + 1.9×H  |  Female = 49 + 1.7×H
Miller (1983): Male = 56.2 + 1.41×H  |  Female = 53.1 + 1.36×H
Devine (1974): Male = 50 + 2.3×H  |  Female = 45.5 + 2.3×H
Hamwi (1964): Male = 48 + 2.7×H  |  Female = 45.5 + 2.2×H

Results are in kg. These are guidelines — consult a doctor for personal health advice.