Kilograms to Grams Converter

One kilogram is a thousand grams — and the only SI base unit whose name already contains a prefix.

Conversion table

Weight	In grams
0.5	500 g
1	1,000 g
1.5	1,500 g
2	2,000 g
2.5	2,500 g
3	3,000 g
4	4,000 g
5	5,000 g
6	6,000 g
7	7,000 g
8	8,000 g
9	9,000 g
10	10,000 g
12	12,000 g
15	15,000 g

🥣 Weights worth knowing

1 kg1,000 g
1 kg2.2046 lb
500 g17.64 oz
1 tonne1,000 kg

Weighing without slips

Baking by weight beats baking by volume. A cup of flour ranges from about 120 to 150 grams depending on how it was scooped; 125 g is 125 g every time.
Kitchen scales usually switch between grams and ounces with one button. Check which is lit before you trust a number under 100.
Airline allowances are almost always in kilograms outside North America: 23 kg is the common checked limit, which is 50.7 lb.
Medicine doses are in milligrams, and a thousandth of a gram matters there — never round a dose the way you would round flour.

A thousand grams, and one odd prefix

The conversion is a decimal point: 1.5 kg is 1,500 g and 250 g is 0.25 kg. What makes the kilogram unusual is that it is the only SI base unit whose name already carries a prefix. That is a historical accident — the original standard was to be called the grave, and the gram was defined as a thousandth of it — and it leaves one awkward rule behind: prefixes are built on the gram, not on the kilogram. A million kilograms is a gigagram, not a kilokilogram, though in practice everyone says tonne, which is exactly 1,000 kg.

The cylinder that used to be the kilogram

Until 2019, the kilogram was a physical object: a platinum-iridium cylinder held in a vault near Paris, with official copies distributed to national laboratories. Comparisons over 130 years showed the copies and the original slowly diverging, by around fifty micrograms — small, but the standard is supposed to be the thing that does not change. The 2019 revision replaced it by fixing the Planck constant at exactly 6.62607015 × 10⁻³⁴ joule-seconds, letting a Kibble balance realise a kilogram from electrical measurements. No scale in any kitchen noticed, but the unit is now reproducible anywhere.

Weights in the kitchen

Plain flour: about 125 g per US cup, though scooping instead of spooning can push it to 150 g.
Granulated sugar: about 200 g per cup; brown sugar packed, about 220 g.
Butter: a US stick is 113 g, a European block usually 250 g.
Bread baking uses baker's percentages, where every ingredient is a percentage of flour weight — impossible with cups.
A large egg is roughly 50 g without the shell, which is why recipes scale cleanly in grams.
Yeast, salt and spices are where grams matter most: 7 g of instant yeast is one sachet, and 10 g is a very different loaf.

A sense of everyday scale

A paperclip is about 1 g; a sheet of A4 paper about 5 g.
A litre of water weighs 1 kg, which is exactly how the unit was originally conceived.
A newborn averages 3.4 kg; airline hand luggage is often capped at 7–10 kg.
A bag of cement is 25 kg in Europe and 94 lb (42.6 kg) in the United States.
A tonne is 1,000 kg — a small car is roughly 1.2 to 1.5 tonnes.
Medicine works in milligrams: a standard paracetamol tablet is 500 mg, or half a gram.

Worked examples

Both directions, kitchen and parcel

A recipe calls for 1.5 kg

1.5 × 1,000 = 1,500 g
In pounds: 1.5 × 2.20462 = 3.31 lb
In ounces: 52.9 oz

1.5 kg = 1,500 g = 3.31 lb

A parcel weighs 750 g

750 ÷ 1,000 = 0.75 kg
0.75 × 2.20462 = 1.65 lb
Most couriers round up to the next 500 g band

750 g = 0.75 kg = 1.65 lb

Frequently Asked Questions

How many grams are in a kilogram?

Exactly 1,000. The prefix kilo means a thousand throughout the SI, so converting is simply moving the decimal point three places: 2.5 kg is 2,500 g and 400 g is 0.4 kg.

How many pounds is 1 kg?

2.20462 pounds. The relationship is exact by definition, because the international avoirdupois pound was fixed at 0.45359237 kg in the 1959 agreement between the English-speaking countries. For a rough figure, double the kilograms and add 10%.

Why is the kilogram the base unit instead of the gram?

History. The metric system's original mass standard was a physical artefact of about a kilogram, and the gram was defined from it rather than the other way round. The oddity is visible in the naming rules: prefixes attach to the gram, so a millionth of a kilogram is a milligram and never a microkilogram.

Is 1 litre of water exactly 1 kilogram?

Very nearly, and that was the intention. The gram was originally defined as the mass of a cubic centimetre of water at its densest point, so a litre came out at almost exactly a kilogram. Modern definitions are independent of water, and the real figure varies slightly with temperature — about 0.998 kg at room temperature.

Why did the kilogram get redefined in 2019?

Because it was still a physical object, and physical objects change. The platinum-iridium prototype drifted about fifty micrograms relative to its official copies over 130 years, which is unacceptable in a standard. Fixing the Planck constant replaced the artefact with a constant of nature that any properly equipped laboratory can realise.

Should I bake in grams or in cups?

Grams, whenever the recipe allows it. A cup measures volume, and the same cup of flour can hold 120 to 150 grams depending on how it was filled — a swing of up to a quarter, which is the difference between a tender crumb and a dense one. Weight removes the variable entirely.