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Grams to kilograms

Multiply grams by 0.001 to get kilograms.

1 g = 0.001 kgBIPM SI
g
1kg

1,000 g = 1 kg

How to convert grams to kilograms

The kilogram is the SI base unit of mass, fixed since 2019 by defining the Planck constant as exactly 6.62607015×10⁻³⁴ J·s. The gram is one thousandth of a kilogram (10⁻³ kg) in the SI.

Worked example — 1,000 g: 1,000 × 0.001 = 1 kg.

Grams to kilograms table

Common conversions. The reverse table is on kilograms to grams.
GramsKilograms
100 g0.1 kg
250 g0.25 kg
500 g0.5 kg
750 g0.75 kg
1,000 g1 kg
2,000 g2 kg
5,000 g5 kg
10,000 g10 kg

Reverse and related

About grams and kilograms

Gram (g)

1 g = 0.001 kg

Definition. One thousandth of a kilogram (10⁻³ kg) in the SI

History and origin

The gram was the original base of the metric system set out in 1795, defined as the mass of one cubic centimetre of water at the melting point of ice, before the larger kilogram was chosen as the SI base unit. It is now simply one thousandth of a kilogram.

Current use

Grams are the everyday metric unit for small masses: recipe ingredients, nutrition labels, medicine doses and postage.

Source: BIPM, The International System of Units (SI), 9th ed. (2019)

Kilogram (kg)

1 kg = 1,000 g

Definition. The SI base unit of mass, fixed since 2019 by defining the Planck constant as exactly 6.62607015×10⁻³⁴ J·s

History and origin

The kilogram began in 1795 as the mass of one litre of water at the melting point of ice, and from 1889 was embodied in a platinum-iridium cylinder kept near Paris, the International Prototype Kilogram. In 2019 the SI retired that physical artefact and redefined the unit through a fixed value of the Planck constant, leaving its size unchanged.

Current use

It is the base unit of mass almost everywhere on Earth. The main everyday exception is the United States, where people weigh in pounds even though US science, medicine and industry work in kilograms.

Source: BIPM, The International System of Units (SI), 9th ed. (2019)

Where people use this

Grams: recipe and food weights, nutrition labels, postage. Kilograms: body weight outside the US, groceries and produce, checked-luggage limits. 500 g is 0.5 kg.

How we know this is right
The factor is fixed by the standards that define the units, not chosen — so it is exact, not a measurement:
1 kg = 1,000 g, so 1 g = 1 ÷ 1,000 = 0.001 kg.

Every value is carried to full double precision; the display is rounded.

Both units are defined in BIPM, The International System of Units (SI), 9th ed. (2019).

Questions people ask

How many kg is 500 grams?

500 grams is 0.5 kilograms. To convert grams to kg, divide by 1000.

How many grams make a kilogram?

It takes exactly 1000 grams to make one kilogram.

What is 750 g in kg?

750 grams is 0.75 kilograms, and 2000 g is 2 kg.

All gram conversions