Ounces to milligrams – convert oz to mg
Convert ounces to milligrams (oz to mg) when you have imperial weights but need precise metric values. This page opens the main mass converter with oz → mg pre-selected.
Open the interactive oz → mg converter:
Use main converter (oz → mg) or switch to mg → ozThe homepage mass tool also converts between ounces, pounds, grams, kilograms, milligrams, stones and tonnes.
Quick reference: ounces to milligrams
One ounce is roughly 28,349.52 mg. So: mg = oz × 28,349.5231. Examples:
| Mass (oz) | Mass (mg, approx.) |
|---|---|
| 0.25 oz | 7,087.38 mg |
| 0.5 oz | 14,174.76 mg |
| 1 oz | 28,349.52 mg |
| 2 oz | 56,699.05 mg |
| 4 oz | 113,398.10 mg |
| 8 oz (½ lb) | 226,796.19 mg |
Why convert ounces to milligrams?
Ounces to milligrams is helpful when you:
- Convert supplement or medicine doses given in oz into mg.
- Work with precious metals or fine powders measured in milligrams.
- Move data from imperial packaging into metric lab workflows.
- Check dosage calculations where mixing oz, g and mg would be error-prone.
Other mass converters on this site
This converter uses standard avoirdupois ounces (16 oz per pound) and the same definitions as other mass tools on this site.
Page last updated: 4 December 2025.