Convert Grain to Gram
Convert grains to grams instantly. 1 grain = 0.0647989 gram — use the live calculator, the exact formula, a conversion table and worked examples. Also check the Gram to Grain converter for the reverse conversion.
Units explained
Grain
The grain (gr) equals 1/7000 of an avoirdupois pound, about 64.8 milligrams.
Based on the nominal mass of a single barley grain.
Ammunition and bullet mass, archery, and historical pharmacy.
Standardized through the English avoirdupois system and retained in 1959.
Gram
The gram (g) equals one-thousandth of a kilogram.
From Late Latin 'gramma', a small weight or scruple.
The everyday metric unit for food, medicine, and small objects.
Defined in 1795 as the mass of one cubic centimeter of water at melting point.
Grain to Gram conversion formula
The relationship between grains and grams:
To convert grains to grams, multiply the value in grains by 0.0647989. To reverse, multiply grams by 15.4323607345.
How to use this converter
Type a value into the calculator. The result in grams updates as you type. Tap a quick value, copy the result with one click, or use the swap arrow to jump straight to the Gram to Grain converter for the reverse direction.
Step-by-step: convert grains to grams
- Write down the value in grains (gr).
- Multiply that value by the factor 0.0647989.
- The product is the equivalent value in grams (g).
- To reverse, multiply the gram value by 15.4323607345.
Worked examples
Example 1 — Convert 1 gr to g:
1 × 0.0647989 = 0.0647989 g
Example 2 — Convert 100 gr to g:
100 × 0.0647989 = 6.47989 g
Real-world example — Packaging gauge
A 4-grain plastic bag thickness is a common spec for grocery and freezer bags. Converting from grains to grams is what packaging buyers do whenever they bridge US and metric supplier quotes.
4 gr × 0.0647989 = 0.2591956 g
Real-world example — Plastic film and laminate thickness
A 500-grain sheet is a typical spec for ID-card laminates and film overlays. Converting to grams aligns the value with the unit most CAD systems and material datasheets prefer.
500 gr × 0.0647989 = 32.39945 g
Grain to Gram conversion table
Standard reference values for converting grains to grams:
| Grain [gr] | Gram [g] |
|---|---|
| 0.01 | 0.000647989 |
| 0.1 | 0.00647989 |
| 1 | 0.0647989 |
| 2 | 0.1295978 |
| 3 | 0.1943967 |
| 4 | 0.2591956 |
| 5 | 0.3239945 |
| 10 | 0.647989 |
| 20 | 1.295978 |
| 30 | 1.943967 |
| 40 | 2.591956 |
| 50 | 3.239945 |
| 100 | 6.47989 |
| 500 | 32.39945 |
| 1000 | 64.7989 |
Frequently asked questions
How many grams is 1 grain?
How do I convert grains to grams?
How do I convert grams back to grains?
How many grams is 100 grains?
Popular weight unit conversions
Convert Grain to other weight units
Show all Grain conversions
Metric / SI (18 units)
Avoirdupois (14 units)
Troy & Apothecary (10 units)
Indian / South Asian (6 units)
Scientific / Atomic (9 units)
Astronomical (4 units)
Biblical / Ancient (14 units)
Sources & references
Conversion factor (1 gr = 0.0647989 g) verified against the following authoritative sources:
- BIPM — The International System of Units (SI Brochure 9th ed.)
Official BIPM publication defining the seven SI base units (including the meter) and the rules for their use. The global authority on units of measurement.
- NIST — Guide to the SI
US National Institute of Standards and Technology reference covering the SI base and derived units with definitions and usage rules for US technical practice.
- NIST Special Publication 811 — Guide for the Use of the International System of Units
Detailed NIST guide covering exact conversion factors between SI and US customary units along with formatting and rounding conventions.
- NIST — Refinement of values for the yard and pound (Federal Register 1959)
The treaty (signed by US
- International Astronomical Union — System of Astronomical Constants
The IAU defines astronomical units including the AU (149597870700 m exactly) light-year and parsec used in astronomy and astrophysics.