About the mg to t calculation
One milligram is exactly 1.0000e-9 tonnes, so converting between them is a single multiplication. Enter any value above and the result updates as you type. The usual unit for medication doses and nutrient quantities. A metric tonne is exactly 1,000 kg — not the same as a US or imperial ton.
Formula
t = mg × 1.0000e-9
1 mg = 1.0000e-9 t
1 t = 1,000,000,000 mgWorked example
To convert 500 mg, multiply by 1.0000e-9: 500 × 1.0000e-9 = 5.0000e-7 t.
Frequently asked questions
How many tonnes are in a milligram?
There are 1.0000e-9 tonnes in one milligram. To convert any amount, multiply the number of milligrams by 1.0000e-9.
How do I convert tonnes back to milligrams?
Divide instead of multiplying, or equivalently multiply by 1,000,000,000. One tonne is 1,000,000,000 milligrams.
Is this conversion exact?
Yes. Since the international agreement of 1959, the relationship between milligrams and tonnes is defined exactly rather than measured, so the only rounding here is in how many decimal places we show.
Where is each of these units used?
Milligrams: the usual unit for medication doses and nutrient quantities. Tonnes: a metric tonne is exactly 1,000 kg — not the same as a US or imperial ton.
Sources
- NIST Special Publication 811 — Guide for the Use of the International System of Units