Ounce to Grain Converter
Convert Ounce (oz) to Grain (gr) instantly. 1 oz = 437.5 gr.
Mass Converter
26 units available
1 oz = 437.5 gr
Formula:
gr = oz × 437.5With your value: 1 oz = 437.5 gr
How big is that?
Everyday references on a logarithmic scale, all expressed in ounce so you can sanity-check the result.
Other Ounce to Grain conversions
Ounce to Grain Conversion Table
| Ounce (oz) | Grain (gr) |
|---|---|
| 0.5 | 218.75 |
| 1 | 437.5 |
| 2 | 875 |
| 5 | 2,187.5 |
| 10 | 4,375 |
| 15 | 6,562.5 |
| 20 | 8,750 |
| 25 | 10,937.5 |
| 50 | 21,875 |
| 100 | 43,750 |
| 250 | 109,375 |
| 500 | 218,750 |
| 1000 | 437,500 |
Grain to Ounce Conversion Table
| Grain (gr) | Ounce (oz) |
|---|---|
| 0.5 | 0.001143 |
| 1 | 0.002286 |
| 2 | 0.004571 |
| 5 | 0.011429 |
| 10 | 0.022857 |
| 15 | 0.034286 |
| 20 | 0.045714 |
| 25 | 0.057143 |
| 50 | 0.114286 |
| 100 | 0.228571 |
| 250 | 0.571429 |
| 500 | 1.142857 |
| 1000 | 2.285714 |
Where these values come from
Every factor on this page is traced to the document that defines it. See the full provenance dataset or our methodology.
Ounce (oz)
Mass
1 avoirdupois ounce = 1/16 lb = 0.028 349 523 125 kg exactly.
Source: International Yard and Pound Agreement of 1959; NIST Federal Register Notice 59-5442
US, UK, Canada, Australia, New Zealand, South Africa · Reviewed 2026-07-01
Grain (gr)
Mass
Traceable to the kilogram, defined by fixing the Planck constant at 6.626 070 15 × 10⁻³⁴ J·s. Avoirdupois masses derive from the 1959 international pound (0.453 592 37 kg exactly).
Source: BIPM, The International System of Units (SI), 9th edition, 2019 (updated 2024)
Bureau International des Poids et Mesures · Reviewed 2026-07-01
How to Convert Ounce to Grain
To convert from Ounce (oz) to Grain (gr), multiply the value by 437.5.
Formula: gr = oz × 437.5
Reverse: oz = gr × 0.0022857143
Step-by-Step Example
- Start with your value in Ounce. For example: 5 oz
- Multiply by the conversion factor: 5 x 437.5
- The result is: 2,187.5 gr
About Ounce
The ounce (oz) equals 1/16 of a pound or approximately 28.35 grams. It is used for food portions and small weight measurements.
Common uses: food portions, postal mail, precious metals.
About Grain
The grain equals exactly 64.79891 milligrams and was originally the weight of a single barleycorn. It is still the standard unit for bullets, propellant and arrows.
Common uses: ammunition, archery, pharmacy (historic).
Frequently Asked Questions
How many Grain are in 1 Ounce?
There are exactly 437.5 Grain in 1 Ounce. This means the conversion factor from Ounce to Grain is 437.5.
What is the formula to convert Ounce to Grain?
The formula to convert Ounce to Grain is: gr = oz × 437.5. For example, to convert 10 Ounce to Grain, you would multiply 10 by 437.5.
What is a Ounce?
The ounce (oz) equals 1/16 of a pound or approximately 28.35 grams. It is used for food portions and small weight measurements.
What is a Grain?
The grain equals exactly 64.79891 milligrams and was originally the weight of a single barleycorn. It is still the standard unit for bullets, propellant and arrows.
What are the common uses of Ounce?
The Ounce is commonly used in food portions, postal mail, precious metals.
Related Mass Conversions
Cite this page
UnitConvertLab. (2026). Ounce to Grain converter. UnitConvertLab. Retrieved from https://unitconvertlab.com/convert/ounce-to-grain