Your favorite European baking recipe calls for "500 g of flour" and your measuring cups are in cups. At the gym, the dumbbells are marked in pounds but your tracking app wants kilograms. And when you ship a parcel abroad, the carrier quotes in pounds and ounces.
Grams, kilos, pounds and ounces coexist in the kitchen, the gym, shipping and food labels. Converting between them isn't advanced math: it's knowing four factors and a couple of tricks. Let's get to it.
The base: the kilogram
The kilogram is the base unit of mass in the International System. Everything else follows:
- 1 kg = 1000 g
- 1 g = 1000 mg
- 1 metric tonne = 1000 kg
Fun fact: since 2019 the kilogram is no longer defined by a physical object (the famous "master kilo" in Paris) but by the Planck constant. For everyday conversions, nothing changes: the factors stay the same.
Quick weight conversion table
| From | To | Factor |
|---|---|---|
| 1 kg | pounds (lb) | × 2.20462 |
| 1 lb | kg | × 0.453592 |
| 1 ounce (oz) | g | × 28.3495 |
| 1 kg | oz | × 35.274 |
| 1 metric tonne | kg | × 1000 |
| 1 short ton (US) | kg | × 907.185 |
Practical weight conversion examples
- Gym: a 20 kg barbell → 20 × 2.20462 ≈ 44.1 lb. Those American 45 lb plates are actually 20.4 kg.
- Cooking: a pound of meat → 0.453592 kg ≈ 454 g. An ounce of cheese → 28.35 g.
- Shipping: a 5 kg package → 5 × 2.20462 ≈ 11.02 lb. If the rate is per pound, every 0.45 kg counts as one more pound.
Weight in the kitchen: scales don't lie
Anglo-Saxon recipes give dry ingredients in cups and liquids in fluid ounces, but weight is always more reliable: 1 cup of flour weighs about 120 g and 1 cup of sugar about 200 g. If a recipe says "1 lb of butter", that's 454 g (usually 2 cups or 4 sticks). When converting recipes, weigh whenever you can: scales don't fail, cups do.
Weight in shipping and international parcels
Couriers quote in pounds and ounces (US) or kilos (Europe). And watch out for volumetric weight: carriers compare the real weight with the volume (length × width × height ÷ factor) and charge the larger one. A big, light box can cost more than a small, heavy one even though it weighs less.
Common weight conversion mistakes
- Forgetting that 1 lb = 16 oz: it's not decimal.
- Rounding too early: 454 g is not 500 g in a delicate recipe.
- Confusing tonnes: the metric tonne (1000 kg) and the US short ton (907 kg) are different units.
- Mixing weight ounces (28.35 g) with fluid ounces (29.57 ml): completely different units.
FAQ about weight and mass conversion
How many pounds are in 1 kilo?
2.20462 pounds. Mental trick: double and add 10 % (1 kg → 2 + 0.2 = 2.2 lb).
How many grams are in an ounce?
28.3495 grams — call it 28 g and you're close enough for most cooking.
Are weight and mass the same?
Technically no: weight depends on gravity, mass doesn't. But everyday conversions use the same factors.
How many ounces are in a pound?
Exactly 16 ounces.
How much does a cup of flour weigh?
About 120 g; a cup of sugar about 200 g. Weight per volume changes with every ingredient.
Convert kilos, pounds and ounces instantly with the unit calculator — no mental tables, no rounding errors.
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