Result
This page has no server side at all. The table you paste is parsed by JavaScript inside your own browser, the chart is drawn on a canvas element on your machine, and the export file is assembled locally. Nothing is uploaded, stored or written to any log. You can disconnect from the network after the page has loaded and everything will still work — which is the simplest way to verify the claim yourself.
Facts and limits of this method
| Formula | Tonnes = milligrams × factor |
|---|---|
| 1 milligram | 1.00000e-9 tonnes |
| 1 tonne | 1.00000e+9 milligrams |
| Rounding | Adjustable from 0 to 6 decimal places |
When it misleads you
- The ratio for converting milligrams to tonnes is an exactly defined international constant, not a measured approximation (including the pound and ounce, officially fixed by the 1959 international agreement), so the converter doesn't accumulate error regardless of the size of the entered value.
- At "0 — whole number" precision, the fractional part of the result is dropped by standard rounding rules, not truncation.
- The input accepts both a period and a comma as a decimal separator, but doesn't understand thousands-grouping separators — enter the number without them.
- The stone (14 pounds) and the carat (0.2 grams) are units with a fixed but not always obvious conversion factor — if the result looks unexpectedly large or small, check the formula row above.
How it is calculated
The entered value in milligrams is multiplied by the conversion factor into tonnes — this gives the result.
The result is rounded to the chosen number of decimal places using standard mathematical rounding.
The "1 tonne = …" row shows the reverse ratio — one divided by the original factor — so you can quickly check which direction the conversion runs.
The calculation updates instantly on every change to the input field or precision, with no separate button.
Questions and answers
How do I convert milligrams to tonnes?
Enter a value in the field — the converter instantly recalculates it into tonnes using a fixed factor.
Can I enter fractional values?
Yes, the converter accepts decimal values with either a period or a comma as the separator.
How do I change the result's precision?
Pick the number of decimal places you want in the "Precision" dropdown.
Is my data sent anywhere?
No, the whole calculation runs in your browser.