Understand the relationship
Visual explanation
The US gallon contains exactly 128 US fluid ounces and equals 3,785.411784 milliliters. Dividing by 128 produces 29.5735295625 mL per US fluid ounce.
The 30 mL shortcut is convenient, but the difference accumulates. At 32 US fluid ounces, the accurate result is 946.352946 mL—not 960 mL.
Calculate it
The formula
milliliters = US fluid ounces × 29.5735295625Instant converter
Convert while you learn
1 US fluid ounce equals
milliliters
Calculated from the canonical unit dataset.
1 × 29.5735295625 mL ÷ 1 mL
Follow the reasoning
Worked examples
Convert 8 US fluid ounces to milliliters.
8 × 29.5735295625 = 236.58823658 US fl oz = 236.5882365 mL
Convert 12 US fluid ounces to milliliters.
12 × 29.5735295625 = 354.8823547512 US fl oz ≈ 354.882 mL
Convert 32 US fluid ounces to milliliters.
32 × 29.5735295625 = 946.35294632 US fl oz = 946.352946 mL
Quick lookup
US fluid ounce to milliliters chart
| US fluid ounces | milliliters |
|---|---|
| 1 | 29.573529563 |
| 2 | 59.147059125 |
| 4 | 118.29411825 |
| 8 | 236.5882365 |
| 12 | 354.88235475 |
| 16 | 473.176473 |
| 32 | 946.352946 |
Values are generated from the same canonical constants used by the converter. Decimal display may be rounded.
Common mistake
Check the unit and direction
An Imperial fluid ounce equals 28.4130625 mL, so it is slightly smaller than a US fluid ounce. Check the label before choosing a factor.
Remember it
Use 30 mL per US fluid ounce for a quick estimate, then use 29.5735295625 when accuracy matters.
Quick practice
Convert 20 US fluid ounces to milliliters.
591.47059125 mL, or about 591.47 mL.
Accuracy note: Core U.S. liquid relationships and the 231-cubic-inch gallon were checked against NIST Handbook 44 (2026), Appendix C. SI definitions were checked against NIST SI Units—Volume. Imperial values were checked against the UK Weights and Measures Act 1985. Values were last checked on . Review the source list.