This converter turns milligrams into tonnes instantly, using the exact factor 1 milligram = 1e-09 tonnes. Type any number and the result updates as you go — nothing is sent to a server, so the arithmetic happens entirely in your browser.
One thousandth of a gram, the standard unit for medication doses and nutrients. The metric ton: exactly 1,000 kilograms, used for freight and vehicle mass.
Because the relationship is a simple proportion, one multiplication does the whole job. The table further down gives pre-computed values for the amounts people look up most often, and the result panel also reports the reverse conversion so you can check the figure both ways.
The formula
milligrams- The amount you are converting, measured in milligrams
1e-09- The exact number of tonnes in one milligram
tonnes- The converted result
How it works, step by step
- Enter the number of milligrams you want to convert.
- The value is multiplied by 1e-09, the exact conversion factor.
- The result is displayed in tonnes, rounded for readability.
- The unrounded value and the reverse conversion appear underneath so you can verify it.
Worked examples
Converting 5 milligrams
Multiply 5 by 1e-09. That gives 5.0000e-09 tonnes. A quick sanity check: one milligram is smaller than one tonne, so the number should get smaller — and it does.
Converting 72 milligrams
72 × 1e-09 = 7.2000e-08 tonnes. Working backwards, 7.2000e-08 ÷ 1e-09 returns 72 milligrams, which confirms the factor is applied the right way round.
How to read your score
Frequently asked questions
How many tonnes are in one milligram?
Exactly 1e-09. Every conversion on this page is that single number multiplied by your input, so the result carries no rounding error beyond what is shown.
What is the formula to convert milligrams to tonnes?
Tonnes = milligrams × 1e-09. To reverse it, divide instead: milligrams = tonnes ÷ 1e-09, which is the same as multiplying by 1000000000.
Is the milligram bigger than the tonne?
No. One milligram is only 1e-09 of a tonne, so the tonne is the larger unit.
Why does my answer differ slightly from other mg to tonnes converters?
Most differences come from rounding the factor too early. This tool keeps full double precision through the calculation and only rounds at the final display step, and it also shows the unrounded value so you can see exactly where any difference appears.
What is a milligram?
One thousandth of a gram, the standard unit for medication doses and nutrients.
What is a tonne?
The metric ton: exactly 1,000 kilograms, used for freight and vehicle mass.
Milligrams to tonnes reference table
| Milligrams | Tonnes |
|---|---|
| 0.5 mg | 5.0000e-10 t |
| 1 mg | 1.0000e-09 t |
| 2 mg | 2.0000e-09 t |
| 3 mg | 3.0000e-09 t |
| 5 mg | 5.0000e-09 t |
| 10 mg | 1.0000e-08 t |
| 15 mg | 1.5000e-08 t |
| 20 mg | 2.0000e-08 t |
| 25 mg | 2.5000e-08 t |
| 50 mg | 5.0000e-08 t |
| 75 mg | 7.5000e-08 t |
| 100 mg | 1.0000e-07 t |
| 250 mg | 2.5000e-07 t |
| 500 mg | 5.0000e-07 t |
| 1000 mg | 0.000001 t |
Exact factor: 1 milligram = 1e-09 tonnes. Values rounded for display.