Convert Ounces to Grains
1 ounce (oz) equals 437.5 grains (gr).
1 oz = 437.5 gr
Type in either box. Scientific notation works: 1.5e-3.
Converting a list? Use the bulk ounce to grain converter to paste a column from Excel.
How to Convert Ounce to Grain
- 1 oz = 437.5 gr
- 1 gr = 0.002285714286 oz
- Example: convert 15 oz to gr: 15 oz = 15 × 437.5 gr = 6562.5 gr
Reference conditions. oz: Avoirdupois system: 1 lb = 16 oz = 7000 grains = 0.45359237 kg exactly (1959 agreement). gr: Avoirdupois system: 1 lb = 16 oz = 7000 grains = 0.45359237 kg exactly (1959 agreement).
Formula
gr = oz × 437.5
Derivation from SI units:
- 1 oz = 1/16 lb = 28.349523125 g (exact)
- 1 gr = 1/7000 lb = 64.79891 mg (exact)
- 1 oz = 0.028349523125 kg ÷ 0.00006479891 kg per gr = 437.5 gr
Both units are defined exactly, so the factor is exact. Ounce definition: ounce; Grain definition: grain.
Worked examples
- A reading of 4 oz converts to 1750 gr.
4 oz × 437.5 = 1750 gr - A value of 12 oz is 5250 gr.
12 oz × 437.5 = 5250 gr
Ounce to Grain conversion table
| Ounces (oz) | Grains (gr) |
|---|---|
| 0.25 oz | 109.375 gr |
| 0.5 oz | 218.75 gr |
| 1 oz | 437.5 gr |
| 2 oz | 875 gr |
| 3 oz | 1312.5 gr |
| 4 oz | 1750 gr |
| 5 oz | 2187.5 gr |
| 6 oz | 2625 gr |
| 8 oz | 3500 gr |
| 10 oz | 4375 gr |
| 12 oz | 5250 gr |
| 16 oz | 7000 gr |
| 20 oz | 8750 gr |
| 24 oz | 10500 gr |
| 32 oz | 14000 gr |
| 64 oz | 28000 gr |
Where it's used
Ounces are used for food and parcel weights in the US, while grains appear in bullet and powder weights. Both measure mass (commonly called weight), so the conversion is a fixed factor.
Ounce to other weight and mass units
| Conversion | 1 oz equals |
|---|---|
| ounce to kilogram | 0.02834952313 kg |
| ounce to gram | 28.34952313 g |
| ounce to milligram | 28349.52313 mg |
| ounce to microgram | 28349523.13 µg |
| ounce to metric ton | 0.00002834952313 t |
| ounce to pound | 0.0625 lb |
| ounce to stone | 0.004464285714 st |
| ounce to short ton | 0.00003125 ton (US) |
| ounce to long ton | 0.00002790178571 ton (UK) |
| ounce to grain | 437.5 gr |
| ounce to troy ounce | 0.9114583333 oz t |
| ounce to carat | 141.7476156 ct |
Frequently asked questions
How many grains are in 1 ounce?
1 oz = 437.5 gr.
How do I convert ounces to grains?
Multiply the value in oz by 437.5. For example, 15 oz × 437.5 = 6562.5 gr.
Is the oz to gr conversion exact?
Yes. Both units are defined exactly, and 1 oz is exactly 437.5 gr.
Sources
- Guide for the Use of the International System of Units (SI), NIST Special Publication 811, 2008 Edition, National Institute of Standards and Technology , Appendix B.8, "ounce (avoirdupois) (oz)".
- Guide for the Use of the International System of Units (SI), NIST Special Publication 811, 2008 Edition, National Institute of Standards and Technology , Appendix B.8, "grain (gr)".
Last reviewed: . Factors are stored exactly and computed with 50-digit decimal arithmetic. See how we verify conversion factors.
Cite this page
APA
Scientific Converters. (2026, October 15). Convert Ounces to Grains. Retrieved October 17, 2026, from https://scientificconverters.com/mass/ounces-to-grains/
IEEE
Scientific Converters, "Convert Ounces to Grains," scientificconverters.com. Accessed: Oct. 17, 2026. [Online]. Available: https://scientificconverters.com/mass/ounces-to-grains/