How to Convert Kilograms to Milligrams (kg to mg)

Updated 5 Oct 2026 in Unit Converters

Weight units matter at the wet market, where older stalls and Chinese medical halls still quote prices per kati or tael, and when following American recipes in ounces and pounds. This guide shows how to convert kilograms into milligrams by hand, with examples and a quick-reference table.

The conversion

To convert kilograms to milligrams, multiply the value by 1,000,000. To go the other way, divide by the same number (or multiply by 1.000000e-06). For a quick estimate, multiply by about 1,000,000.

Milligrams = kilograms × 1,000,000

Worked examples

Kilograms to Milligrams table

KilogramsMilligrams
1 kg1,000,000 mg
2 kg2,000,000 mg
5 kg5,000,000 mg
10 kg10,000,000 mg
20 kg20,000,000 mg
25 kg25,000,000 mg
50 kg50,000,000 mg
100 kg100,000,000 mg
250 kg250,000,000 mg
500 kg500,000,000 mg
1,000 kg1,000,000,000 mg

Common questions

Is kg to mg exact?

The factors used here are the internationally defined values where they exist; results are rounded for display only.

How do I convert back?

Use the Milligrams to Kilograms converter.

Mistakes to avoid

Rounding the factor too early

Using 3 instead of 3.28 for feet per metre introduces an error of almost 9% before you have started.

Dropping the units

A bare number without a unit is easy to misread later. Always write the unit with the result.

Forgetting squared and cubed units

Area and volume factors are the length factor squared or cubed, so 1 m² is about 10.76 sq ft, not 3.28.

Background

A conversion table is handy for common values, but a calculator is faster and avoids interpolation errors for anything in between.

Unit conversion is simply multiplication by a fixed ratio. The ratio between two units of the same quantity never changes, so once you know it you can convert any value in either direction.

For everyday use, three or four significant figures are usually enough. Engineering, science and trade documents may need more, and rounding should happen only at the end of a calculation.

For any value, use the Kilograms to Milligrams Converter or browse all weight converters.

Run your own numbers: Kilograms to Milligrams Converter

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