---
title: "21 mg to t = 2.1 × 10^-8 t"
description: "21 milligrams is 2.1 × 10^-8 tonnes. The arithmetic, a table of nearby values, and a converter for any other number."
url: https://atoneplace.net/convert/21-mg-to-tonnes/
site: "At One Place"
---

# 21 mg to t

**21 milligrams in tonnes: 21 mg = 2.1 × 10^-8 t**

t = mg × 1 × 10^-9

21 milligrams is 2.1 × 10^-8 tonnes. To get there, multiply by 1 × 10^-9.

## Values either side

*Milligrams near 21, converted to tonnes.*

| Milligrams | Tonnes |
| --- | --- |
| 17 mg | 1.7 × 10^-8 |
| 18 mg | 1.8 × 10^-8 |
| 19 mg | 1.9 × 10^-8 |
| 20 mg | 2 × 10^-8 |
| 21 mg ← | 2.1 × 10^-8 |
| 22 mg | 2.2 × 10^-8 |
| 23 mg | 2.3 × 10^-8 |
| 24 mg | 2.4 × 10^-8 |
| 25 mg | 2.5 × 10^-8 |

## How the conversion works

The relationship is t = mg × 1 × 10^-9. Both units measure mass, so the conversion is a fixed factor that never changes.

> Tonne: Also called a metric ton.

## Common questions

### What is 21 mg in tonnes?

21 mg is 2.1 × 10^-8 t.

### How do you convert milligrams to tonnes?

Multiply by 1 × 10^-9.

## Related pages

- [Milligrams to tonnes](https://atoneplace.net/convert/mg-to-tonnes/)
- [21 t to mg](https://atoneplace.net/convert/21-tonnes-to-mg/)
- [17 mg to t](https://atoneplace.net/convert/17-mg-to-tonnes/)
- [18 mg to t](https://atoneplace.net/convert/18-mg-to-tonnes/)
- [19 mg to t](https://atoneplace.net/convert/19-mg-to-tonnes/)
- [20 mg to t](https://atoneplace.net/convert/20-mg-to-tonnes/)
- [22 mg to t](https://atoneplace.net/convert/22-mg-to-tonnes/)
- [23 mg to t](https://atoneplace.net/convert/23-mg-to-tonnes/)
- [24 mg to t](https://atoneplace.net/convert/24-mg-to-tonnes/)
- [25 mg to t](https://atoneplace.net/convert/25-mg-to-tonnes/)

## Sources

- Guide for the Use of the International System of Units (SP 811) — NIST (https://www.nist.gov/pml/special-publication-811) [Public domain (US Government)]
- The International System of Units (SI Brochure) — Bureau International des Poids et Mesures (https://www.bipm.org/en/publications/si-brochure)
- Calculated on this page — At One Place (/about/)