How many grains are in one tonne?

One tonne equals approximately 15,432,358.3529 grains. This follows from the exact definition 1 grain = 64.79891 mg = 6.479891 × 10⁻⁸ t.

Is the grain used in troy or avoirdupois systems?

The grain is the same unit in both systems — 1 grain = 64.79891 mg regardless of whether you are using troy, avoirdupois, or apothecaries weight.

What is a tonne (metric ton)?

A tonne is a metric unit of mass equal to 1,000 kilograms or 1,000,000 grams. It is different from the US short ton (907.18 kg) and the UK long ton (1,016.05 kg).

How accurate is this converter?

The converter uses the internationally agreed exact definition: 1 grain = 64.79891 mg. Results are displayed to up to 10 significant figures to cover very large grain values.

Can I convert tonnes back to grains?

Yes — multiply the tonne value by approximately 15,432,358.3529 to get grains. This tool converts grains → tonnes; for the reverse, use a tonnes-to-grains converter.

Grains to Tonnes Converter

Enter a value in grains and instantly get the equivalent mass in tonnes (metric tons).

Grains Input

Value in Grains (gr)

Result

Enter a grain value to see the result

Common Conversion Reference

Grains (gr)	Tonnes (t)

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Summary

The Grains to Tonnes Converter translates mass values from the grain (gr), a traditional unit used in pharmacy, ballistics, and precious-metal trading, into tonnes (t), the SI-aligned metric unit equal to 1,000 kilograms. One grain equals exactly 64.79891 milligrams, making one tonne equal to approximately 15,432,358.35 grains. The conversion is performed entirely in your browser with no data sent to any server.

How it works

Type a mass value in grains into the input field.
The converter applies the exact factor: 1 grain = 6.479891 × 10⁻⁸ tonnes.
The result in tonnes appears instantly below the input.
Use the quick reference table to see common conversions at a glance.
Click "Copy Result" to copy the converted value to your clipboard.

Use cases

Ballistics engineers converting bullet or powder charges to metric mass.
Pharmacists and compounding chemists verifying grain-based dosage in SI units.
Precious-metal traders converting troy-grain weights to tonne-level totals.
Lab technicians cross-checking sample masses recorded in archaic units.
Students completing unit-conversion homework or exam problems.
Import/export documentation requiring metric mass values.

Frequently Asked Questions

Last updated: 2026-06-04 · Reviewed by Nham Vu