# How do I convert kg/m3 to g/cm3?

Converts kilograms per cubic meter (kg/m³) to grams per cubic centimeter (g/cm³) and back, with the exact unit definitions.

- Page: https://www.acalculator.org/convert/kg-m3-to-g-cm3
- JSON spec: https://www.acalculator.org/convert/kg-m3-to-g-cm3.json
- Version: 95c11b9f5a31

## Default answer

Example with the default inputs (Kilograms per cubic meter (kg/m³) 1): 1 kg/m³ = 0.001 g/cm³.

## Inputs

| Key | Label | Description |
| --- | --- | --- |
| value | Kilograms per cubic meter (kg/m³) | The amount in kilograms per cubic meter to convert. |
| result | Grams per cubic centimeter (g/cm³) | The same amount in grams per cubic centimeter. |

## Outputs

| Key | Label | Description |
| --- | --- | --- |
| value | Kilograms per cubic meter (kg/m³) | The amount in kilograms per cubic meter to convert. |
| result | Grams per cubic centimeter (g/cm³) | The amount in grams per cubic centimeter. |

## Method

g/cm³ = kg/m³ × 0.001

## Assumptions

- 1 kilogram per cubic meter = 0.001 grams per cubic centimeter, 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; an answer of 1 billion or more shows at most 15 significant digits.

## Worked examples

1. value = 1 gives result = 0.001. Source: Exact unit definitions in NIST SP 811 (2008), Appendix B.8.
2. value = 1,000 gives result = 1. Source: Exact unit definitions in NIST SP 811 (2008), Appendix B.8.
3. result = 1 gives value = 1,000. Source: Exact unit definitions in NIST SP 811 (2008), Appendix B.8.

## FAQ

### How many grams per cubic centimeter are in a kilogram per cubic meter?

1 kilogram per cubic meter is 0.001 grams per cubic centimeter, from the exact unit definitions (NIST SP 811).

### How do I convert kg/m3 to g/cm3?

Multiply by 0.001: g/cm³ = kg/m³ × 0.001. For example, 1 kg/m³ × 0.001 = 0.001 g/cm³.

### How do I convert g/cm3 back to kg/m3?

Multiply by 1,000, or type the grams per cubic centimeter into the second box and the converter works it out. 1 gram per cubic centimeter is 1,000 kilograms per cubic meter.

### Why divide by 1,000?

A gram is 0.001 kg and a cubic centimeter is 0.000001 m³ (SI prefixes), so 1 g/cm³ = 0.001 kg ÷ 0.000001 m³ = 1,000 kg/m³ exactly.

### What is the density of water in g/cm³?

Pure water is 999.9749 kg/m³ at 4 °C, where it is densest, which is 0.999975 g/cm³, and 998.2067 kg/m³ at 20 °C, 0.998207 g/cm³ (Tanaka et al. 2001).

## Sources

- NIST SP 811 (2008), Guide for the Use of the International System of Units, Appendix B.8: Factors for Units Listed Alphabetically (bold factors are exact), retrieved 2026-10-19. https://www.nist.gov/pml/special-publication-811/nist-guide-si-appendix-b-conversion-factors/nist-guide-si-appendix-b8
- NIST SP 811 (2008), Chapter 4, Table 5: SI prefixes (kilo 10³, centi 10⁻², milli 10⁻³), retrieved 2026-10-19. https://www.nist.gov/pml/special-publication-811/nist-guide-si-chapter-4-two-classes-si-units-and-si-prefixes
- Tanaka, M. et al. (2001), Recommended table for the density of water between 0 °C and 40 °C based on recent experimental reports, Metrologia 38, 301–309: pure water 999.9749 kg/m³ at 4 °C and 998.2067 kg/m³ at 20 °C, retrieved 2026-10-19. https://doi.org/10.1088/0026-1394/38/4/3