Convert Grain to Metric Ton (grt)

The grain is the smallest traditional weight unit, used in pharmaceutical compounding, ammunition, and arrow tips.

6.48 × 10^-8
1 gr6.48 × 10^-8 tNIST · BIPM accuracy

Grain to Metric Ton Conversion Table

10 common values
GrainMetric Ton
1 gr6.48 × 10^-8 t
5 gr3.24e-7 t
10 gr6.48e-7 t
25 gr0.00000162 t
50 gr0.00000324 t
100 gr0.00000648 t
250 gr0.0000162 t
500 gr0.0000324 t
1,000 gr0.0000648 t
5,000 gr0.000324 t

How to Convert Grain to Metric Ton Manually

Step by Step

Converting grains to metric tons is straightforward: multiply by the conversion factor. Follow these three steps to do it by hand or in your head.

  1. 1
    Take your value in grains
    Start with the number of grains (gr) you want to convert.
  2. 2
    Multiply by 6.48 × 10^-8
    The conversion factor from gr to t is 6.48 × 10^-8. Multiply your value by this number.
  3. 3
    Read the result in metric tons
    The result is your value in metric tons (t).
Practical Examples
1 gr
equals
6.48 × 10^-8 t
5 gr
equals
3.24e-7 t
10 gr
equals
6.48e-7 t
25 gr
equals
0.00000162 t
100 gr
equals
0.00000648 t

Formula

Multiply the value in grains by 6.48 × 10^-8. For the reverse direction, multiply by 15,432,358.

Forwardt = gr × 6.48 × 10^-8
Reversegr = t × 15,432,358
Example: 10 gr × 6.48 × 10^-8 = 6.48e-7 t

Tips

Use these in everyday conversions
  • 1 grain = 64.79891 mg exactly. 7000 grains = 1 pound.
  • Ballistics is one of the few modern contexts where grains are essential.
  • Some older pharmacology dosing survives in grain units — 5 gr ≈ 325 mg.

Common Mistakes

Avoid these
  • Confusing the grain (mass) with the troy grain in older precious-metal contexts — they are identical (64.8 mg).
  • Assuming "grain" refers to an amount of cereal — in firearms it is always a weight.
  • Reading "5 gr" as 5 grams — it is 5 grains (324 mg).

About Grain and Metric Ton

What is the Grain?

The grain equals exactly 64.79891 milligrams (0.06479891 g) and is the smallest unit in the traditional avoirdupois weight system. Originally based on the average mass of a single grain of wheat or barley, the unit was standardized to its current value with the 1959 international yard and pound agreement. The grain is still used in pharmaceutical compounding (some older drug formulations specify grains, especially aspirin and codeine), arrow tips and ammunition (bullet weights are commonly given in grains — a 9 mm bullet is around 115 grains), and precious-metal weighing (one troy ounce = 480 grains). It relates to the ounce (437.5 grains = 1 oz avoirdupois), the pound (7,000 grains = 1 lb), and the milligram (1 grain ≈ 64.8 mg). The unit reflects medieval agriculture's role in shaping early measurement systems.

  • Bullet and gunpowder mass in ballistics
  • Older pharmaceutical dosing in Anglo-Saxon countries
  • Arrow shaft and archery equipment weights
Real-world examples

A 9 mm bullet typically weighs 115–124 grains (7.45–8.03 g). Aspirin grain dosing: "5 grain aspirin" = 325 mg.

What is the Metric Ton?

The metric ton (or tonne) equals exactly 1,000 kilograms and is the international standard for shipping, agriculture, construction, and industrial weight. Adopted as part of the SI system, the metric ton is used worldwide for bulk commodities (grain harvests measured in tons per hectare), vehicle and shipping container masses, freight rates, and CO₂ emissions accounting. A standard 20-foot shipping container has a maximum gross weight of about 24 metric tons. The metric ton is distinct from the US short ton (907.185 kg) and the UK long ton (1,016.047 kg). The unit's spelling differs by country — 'tonne' in British and international usage, 'metric ton' in American — but the abbreviation 't' is universal. It relates to the kilogram (1,000 kg = 1 t) and the megagram (1 Mg = 1 t).

  • International shipping and freight
  • Agricultural yield (grain, sugar, coffee)
  • Steel, cement and industrial production
Real-world examples

A mid-size car weighs about 1.5 t. A 20-ft shipping container holds up to 28 t. Global steel output is about 1,900 million tonnes per year.

Learn About Both Units

⚖️ Reference

What is the Grain?

Read the unit page →
⚖️ Reference

What is the Metric Ton?

Read the unit page →

Grain to Metric Ton FAQ

5 questions
How many metric tons in a grain?
One grain equals 6.48 × 10^-8 metric tons.
How do I convert grains to metric tons?
Multiply the grain value by 6.48 × 10^-8 to get the equivalent in metric tons.
What is 100 grains in metric tons?
100 grains equals 0.00000648 metric tons.
Is a grain bigger than a metric ton?
No. 1 grain equals 6.48 × 10^-8 metric tons, so one grain is smaller.
How to convert grains to metric tons without a calculator?
Multiply by 0 for a quick estimate; use a calculator for precise results.

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