Weight and Mass Converter

Kilogram (kg)

The SI base unit of mass, defined as the mass of the international prototype kilogram. Used for all scientific and most everyday measurements.

Common uses: Body weight, cooking, nutrition, scientific measurements, product specifications.

Gram (g)

One thousandth of a kilogram. 1 kg = 1000 g. Standard metric unit for smaller quantities.

Common uses: Cooking ingredients, medicine dosages, jewelry, food labels, lab work.

Pound (lb or lbs)

Imperial unit of weight. 1 lb = 0.453592 kg = 16 oz. Standard in USA, UK, and other Commonwealth countries.

Common uses: Body weight (US/UK), package weight, recipes, nutrition info, grocery items.

Ounce (oz)

Imperial unit, one sixteenth of a pound. 1 oz = 28.3495 g = 1/16 lb. Common in cooking and nutrition.

Common uses: Cooking measurements, nutrition labels, small package weights, precious metals.

Ton (metric)

Large metric unit. 1 metric ton = 1000 kg = 2204.62 lbs. Also called tonne, standard for heavy items.

Common uses: Industrial materials, vehicle capacity, cargo weight, construction materials.

Stone (UK)

British unit equal to 14 pounds. 1 stone = 6.35029 kg = 14 lbs. Common for body weight in UK.

Common uses: UK body weight (often with additional pounds, e.g., "11 stone 4 pounds").

Carat (ct)

Unit for precious stones and pearls. 1 carat = 200 mg = 0.2 g. Larger carat = more valuable (in gemstones).

Common uses: Gemstone weight, diamond rating, precious metals (troy weight for gold is different).

Ton (short/US)

US customary unit. 1 short ton = 2000 lbs = 907.185 kg. Different from metric and long ton.

Common uses: US commercial weight, industry standards, cargo capacity in USA.

Ton (long/UK)

Imperial unit. 1 long ton = 2240 lbs = 1016.05 kg. Traditional British ton.

Common uses: UK and Commonwealth countries, historical commerce, shipping.

Grain (gr)

Very small unit. 1 grain = 64.8 mg. Historically used for medicine and ammunition.

Common uses: Ammunition specifications, historical pharmaceutical dosages.

Weight Conversions Quick Reference

• 1 Kilogram: 1000 g = 2.20462 lbs = 35.274 oz = 0.157473 stone
• 1 Pound: 453.592 g = 0.453592 kg = 16 oz
• 1 Ounce: 28.3495 g = 0.0625 lbs
• 1 Stone: 14 lbs = 6.35029 kg = 224 oz
• 1 Metric Ton: 1000 kg = 2204.62 lbs ≈ 1.10231 short tons
• 1 Short Ton (US): 2000 lbs = 907.185 kg
• 1 Long Ton (UK): 2240 lbs = 1016.05 kg
• Typical human weight: 60-90 kg (132-198 lbs, 9.5-14 stone)
• Atomic mass unit: 1.66054 × 10⁻²⁷ kg

Important: Mass vs Weight

• Mass: Amount of matter (constant everywhere, measured in kg)
• Weight: Force of gravity on mass (varies by location, measured in newtons)
• Weight formula: Weight = Mass × g (where g ≈ 9.81 m/s² on Earth)
• On Moon: Same mass weighs ~17% as much (Moon gravity ≈ 1/6 Earth)
• On Jupiter: Same mass weighs ~2.5× as much (stronger gravity)
• In space: No weight, but mass remains the same
• This converter: Treats mass and weight as equivalent at standard Earth gravity (9.81 m/s²)

Regional Weight Standards

• Metric system: kilogram (kg), gram (g) - used in most countries
• US/Imperial: pound (lb), ounce (oz) - USA, some Commonwealth countries
• British: stone, pounds, ounces - UK body weight measurement
• For cooking: Grams and milliliters (metric) vs cups and ounces (US)
• For nutrition: Grams (metric) vs ounces (US labels)
• For jewelry: Carats for gems, troy ounces for precious metals (different from regular ounces)
• For industry: Metric tons vs short/long tons depending on region

Common Object Weights for Reference

• Grain of rice: ~20 mg
• Paperclip: ~1 gram
• AA battery: ~23 grams
• Apple: ~150-200 grams
• Liter of water: 1000 grams (1 kg)
• Standard book: 500-1000 grams
• Newborn baby: 3-3.5 kg (6.6-7.7 lbs)
• Adult human: 60-100 kg (132-220 lbs)
• Large car: 1000-1500 kg
• African elephant: 4000-6000 kg
• Blue whale: 100,000-200,000 kg