Grams to Kilograms
An instant grams-to-kilograms converter, with the formula and a reference table below.
| Grams | Kilograms |
|---|---|
| 1 g | 0.001 kg |
| 2 g | 0.002 kg |
| 3 g | 0.003 kg |
| 5 g | 0.005 kg |
| 10 g | 0.01 kg |
| 25 g | 0.025 kg |
| 50 g | 0.05 kg |
| 100 g | 0.1 kg |
How to use
- Enter a value in the Grams field.
- The Kilograms figure appears immediately — no button to press.
- Typing in the Kilograms field converts back to Grams the same way.
- Use the reference table for the values that come up most often.
Grams to Kilograms formula
The factor from grams to kilograms is 0.001.
kg = g × 0.001
Put another way, one gram is exactly 1/1,000 of a kilogram.
Why this factor: the gram and the kilogram are both defined against the kilogram, so dividing one definition by the other gives 0.001 directly. Both definitions are set out in full below.
To go the other way, divide by 0.001 — or use the Kilograms to Grams converter, which is the same calculation reversed.
Worked example
Given 2 g, multiplying by 0.001 yields 0.002 kg.
2 g × 0.001 = 0.002 kg
The converter above does this for any value you type, in either direction.
What is a gram?
A gram is one thousandth of a kilogram, the everyday unit for food and small-object mass.
Definition: Exactly 0.001 kilogram by SI prefix definition.
Where it is used: Nutrition labels, recipes, postal rates, and laboratory weighing.
What is a kilogram?
The kilogram is the SI base unit of mass — the reference for every other mass unit.
Definition: Since 2019 the kilogram has been defined by fixing the Planck constant at exactly 6.62607015×10⁻³⁴ joule-seconds, retiring the physical platinum-iridium cylinder that defined it for 130 years.
Where it is used: Universal in science, trade and everyday weighing outside the United States.
Grams vs Kilograms
The gram is a metric unit while the kilogram is an SI unit. That is why the factor between them is not a round number: the two systems were defined independently and only later tied together by exact agreement.
Frequently asked questions
How many kilograms are in a gram?
One gram equals 0.001 kilograms.
What is the formula to convert grams to kilograms?
Multiply the number of grams by 0.001. To reverse it, divide by 0.001 instead.
How do I convert kilograms back to grams?
Divide by 0.001, which is the same as multiplying by 1000.
How many kilograms are in 10 grams?
10 g works out to 0.01 kg.
How is the gram defined?
Exactly 0.001 kilogram by SI prefix definition.