# How do I convert kg to metric tons?

Converts kilograms (kg) to metric tons (t) and back, with the exact unit definitions.

- Page: https://www.acalculator.org/convert/kg-to-tonnes
- JSON spec: https://www.acalculator.org/convert/kg-to-tonnes.json
- Version: ad2870e7853f

## Default answer

Example with the default inputs (Kilograms (kg) 1): 1 kg = 0.001 t.

## Inputs

| Key | Label | Description |
| --- | --- | --- |
| value | Kilograms (kg) | The amount in kilograms to convert. |
| result | Metric tons (t) | The same amount in metric tons. |

## Outputs

| Key | Label | Description |
| --- | --- | --- |
| value | Kilograms (kg) | The amount in kilograms to convert. |
| result | Metric tons (t) | The amount in metric tons. |

## Method

t = kg × 0.001

## Assumptions

- 1 kilogram = 0.001 metric tons, from the exact definitions in NIST SP 811.
- Exact on the typed decimals: at most 6 decimal places (6 significant digits below 0.0001), rounded half up.

## Worked examples

1. value = 1 gives result = 0.001. Source: Exact unit definitions in NIST SP 811 (2008), Appendix B.8.
2. value = 2,500 gives result = 2.5. Source: Exact unit definitions in NIST SP 811 (2008), Appendix B.8.
3. result = 2.5 gives value = 2,500. Source: Exact unit definitions in NIST SP 811 (2008), Appendix B.8.

## FAQ

### How many metric tons are in a kilogram?

1 kilogram is 0.001 metric tons, from the exact unit definitions (NIST SP 811).

### How do I convert kg to tonnes?

Multiply by 0.001: t = kg × 0.001. For example, 1 kg × 0.001 = 0.001 t.

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

Multiply by 1,000, or type the metric tons into the second box and the converter works it out. 1 metric ton is 1,000 kilograms.

### Is a tonne the same as a metric ton?

Yes. A tonne (t) is the metric ton, exactly 1,000 kg (NIST SP 811). The US short ton is 2,000 lb (907.18474 kg), and the UK long ton is 2,240 lb (1,016.0469088 kg).

### Which ton does this page use?

The metric ton (tonne), 1,000 kg. The kg to tons converter uses the US short ton by default and also offers the metric and long tons.

### How many tonnes is 2,500 kg?

2,500 ÷ 1,000 = 2.5 tonnes (metric tons).

## Sources

- NIST SP 811 (2008), Guide for the Use of the International System of Units, Table 5 (SI prefixes) and Appendix B.8 (factors for units listed alphabetically), retrieved 2026-10-05. https://www.nist.gov/pml/special-publication-811