Kilograms to Grams Converter

A kilogram is 1,000 grams:

grams = kilograms × 1000

Like every metric step, it is a decimal point moved three places — which makes this the conversion where the only real risk is moving it the wrong number of places.

One quirk worth knowing: the kilogram is the only SI base unit whose name carries a prefix. The gram is the derived unit here, not the other way round. Until 2019 the kilogram was defined by a physical cylinder of platinum-iridium kept near Paris; it is now defined by fixing the Planck constant, so it no longer depends on an object that could gain or lose atoms.

Where the conversion is routine:

• Recipes. European recipes give flour in grams and larger quantities in kilograms. 0.5 kg of flour is 500 g, roughly four cups.
• Nutrition labels. Everything on a label is per 100 g, so a 1.5 kg pack is 15 servings of the stated figures.
• Postage. Royal Mail and most European carriers price in gram bands up to 2 kg, then switch to kilogram bands. A parcel at 1.95 kg is 1,950 g, still inside the small-parcel band; at 2.05 kg it moves into the next price tier entirely.
• Gym and medicine. Weight plates are in kilograms; drug doses are in milligrams. A dose of 5 mg per kg for an 80 kg adult is 400 mg — the conversion chain runs kg → mg through a factor of a million, so an order-of-magnitude slip here is dangerous rather than merely wrong.

To convert back, divide grams by 1,000.