This converter turns grains into long tons instantly, using the exact factor 1 grain = 6.37755102e-08 long tons. Type any number and the result updates as you go — nothing is sent to a server, so the arithmetic happens entirely in your browser.
The oldest English mass unit, now used for bullets, arrows and propellant charges. The long ton: 2,240 pounds, historically used in the UK and for shipping displacement.
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
grains- The amount you are converting, measured in grains
6.37755102e-08- The exact number of long tons in one grain
long tons- The converted result
How it works, step by step
- Enter the number of grains you want to convert.
- The value is multiplied by 6.37755102e-08, the exact conversion factor.
- The result is displayed in long tons, rounded for readability.
- The unrounded value and the reverse conversion appear underneath so you can verify it.
Worked examples
Converting 5 grains
Multiply 5 by 6.377551e-08. That gives 3.1888e-07 long tons. A quick sanity check: one grain is smaller than one long ton, so the number should get smaller — and it does.
Converting 72 grains
72 × 6.377551e-08 = 0.000005 long tons. Working backwards, 0.000005 ÷ 6.377551e-08 returns 72 grains, which confirms the factor is applied the right way round.
How to read your score
Frequently asked questions
How many long tons are in one grain?
Exactly 6.37755102e-08. 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 grains to long tons?
Long Tons = grains × 6.37755102e-08. To reverse it, divide instead: grains = long tons ÷ 6.37755102e-08, which is the same as multiplying by 15680000.
Is the grain bigger than the long ton?
No. One grain is only 6.37755e-08 of a long ton, so the long ton is the larger unit.
Why does my answer differ slightly from other grains to uk-tons 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 grain?
The oldest English mass unit, now used for bullets, arrows and propellant charges.
What is a long ton?
The long ton: 2,240 pounds, historically used in the UK and for shipping displacement.
Grains to long tons reference table
| Grains | Long Tons |
|---|---|
| 0.5 gr | 3.1888e-08 ton |
| 1 gr | 6.3776e-08 ton |
| 2 gr | 1.2755e-07 ton |
| 3 gr | 1.9133e-07 ton |
| 5 gr | 3.1888e-07 ton |
| 10 gr | 6.3776e-07 ton |
| 15 gr | 9.5663e-07 ton |
| 20 gr | 0.000001 ton |
| 25 gr | 0.000002 ton |
| 50 gr | 0.000003 ton |
| 75 gr | 0.000005 ton |
| 100 gr | 0.000006 ton |
| 250 gr | 0.000016 ton |
| 500 gr | 0.000032 ton |
| 1000 gr | 0.000064 ton |
Exact factor: 1 grain = 6.37755102e-08 long tons. Values rounded for display.