How do I convert kg to mg?
Type a value in either box, and the answer shows it in the other unit as you type.
- Milligrams (mg)
- 1,000,000
1 kg = 1,000,000 mg.
Milligrams (mg): 1,000,000. 1 kg = 1,000,000 mg.
Milligrams (mg) by kilograms (kg)
How to calculate
Converts kilograms (kg) to milligrams (mg) and back, with the exact unit definitions.
Example with the default inputs (Kilograms (kg) 1): 1 kg = 1,000,000 mg.
Formula: mg = kg × 1000000 (the same as kg ÷ 0.000001)
- 1 kilogram = 1000000 milligrams, from the exact definitions in NIST SP 811.
- The answer shows at most 6 decimal places; the calculation keeps full precision.
Worked examples
Each example is checked against the calculator on every build.
- Kilograms (kg) 1 gives Milligrams (mg) 1,000,000.Source: Exact unit definitions in NIST SP 811 (2008), Appendix B.8
- Kilograms (kg) 0.25 gives Milligrams (mg) 250,000.Source: Exact unit definitions in NIST SP 811 (2008), Appendix B.8
- Milligrams (mg) 250,000 gives Kilograms (kg) 0.25.Source: Exact unit definitions in NIST SP 811 (2008), Appendix B.8
Other questions people ask
How many milligrams are in a kilogram?
1 kilogram is 1,000,000 milligrams, from the exact unit definitions (NIST SP 811).
How do I convert kg to mg?
Multiply by 1,000,000: mg = kg × 1000000 (the same as kg ÷ 0.000001). For example, 1 kg × 1,000,000 = 1,000,000 mg.
How do I convert mg back to kg?
Multiply by 0.000001, or type the milligrams into the second box and the converter works it out. 1 milligram is 0.000001 kilograms.