# How do I convert mg to kg?

Converts milligrams (mg) to kilograms (kg) and back, with the exact unit definitions.

- Page: https://www.acalculator.org/convert/mg-to-kg
- JSON spec: https://www.acalculator.org/convert/mg-to-kg.json
- Version: ecceacf39f80

## Default answer

Example with the default inputs (Milligrams (mg) 1): 1 mg = 0.000001 kg.

## Inputs

| Key | Label | Description |
| --- | --- | --- |
| value | Milligrams (mg) | The amount in milligrams to convert. |
| result | Kilograms (kg) | The same amount in kilograms. |

## Outputs

| Key | Label | Description |
| --- | --- | --- |
| value | Milligrams (mg) | The amount in milligrams to convert. |
| result | Kilograms (kg) | The amount in kilograms. |

## Method

kg = mg × 0.000001

## Assumptions

- 1 milligram = 0.000001 kilograms, from the exact definitions in NIST SP 811.
- The answer shows at most 6 decimal places; the calculation keeps full precision.

## Worked examples

1. value = 1 gives result = 0.000001. Source: Exact unit definitions in NIST SP 811 (2008), Appendix B.8.
2. value = 500 gives result = 0.0005. Source: Exact unit definitions in NIST SP 811 (2008), Appendix B.8.
3. result = 0.0005 gives value = 500. Source: Exact unit definitions in NIST SP 811 (2008), Appendix B.8.

## FAQ

### How many kilograms are in a milligram?

1 milligram is 0.000001 kilograms, from the exact unit definitions (NIST SP 811).

### How do I convert mg to kg?

Multiply by 0.000001: kg = mg × 0.000001. For example, 1 mg × 0.000001 = 0.000001 kg.

### How do I convert kg back to mg?

Multiply by 1,000,000, or type the kilograms into the second box and the converter works it out. 1 kilogram is 1,000,000 milligrams.

## Sources

- NIST SP 811 (2008), Guide for the Use of the International System of Units, Appendix B.8. https://www.nist.gov/pml/special-publication-811