A US fluid ounces to milliliters calculator converts US-style volumes to the metric milliliter using the exact factor 1 fl oz = 29.5735 mL. Enter a value in fluid ounces and the calculator returns the milliliter equivalent.
Useful for translating US recipes for metric kitchens, sharing cocktail recipes internationally (most non-US bartending guides use mL/cl), reading nutrition labels in the metric world, and any setting where the same liquid volume needs both unit systems.
Key takeaway
A US fluid ounce is just under 30 mL, close enough that "1 fl oz = 30 mL" works well as a kitchen mental shortcut, with a 1.4% overestimate. For precision contexts (medicine dosing, chemistry, bartending competitions), use the exact 29.5735 factor. Be careful not to confuse fluid ounces (volume) with weight ounces (mass), the names overlap but the numbers don't.
How it's calculated
The conversion:
milliliters = US fluid oz × 29.5735
The 29.5735 figure derives from the US gallon's definition (3.785412 L ÷ 128 fl oz). For imperial fluid ounces (UK historical), use 28.4131 instead, imperial fluid ounces are about 4% smaller.
Useful conversions for common US measures:
- 1 tsp = 5 mL (close enough; precise = 4.93 mL)
- 1 tbsp = 15 mL (close enough; precise = 14.79 mL)
- 1 fl oz = 30 mL (close enough; precise = 29.57 mL)
- 1 cup = 240 mL (close enough; precise = 236.59 mL)
- 1 pint = 473 mL (16 fl oz)
- 1 quart = 946 mL (32 fl oz; nearly 1 liter)
- 1 gallon = 3,785 mL (128 fl oz; ~3.79 liters)
Notable conversions in cocktails:
- 1 oz pour = 30 mL = 3 cl (centiliters; common in European bar recipes)
- 1.5 oz "shot" = 44 mL (1.5 × 29.57)
- 2 oz pour = 59 mL = 6 cl
Source: NIST exact conversion, 1 US fluid oz = 29.5735 mL
Examples
8 fl oz, standard US cup
- Volume 8 fl oz
8 fl oz (1 US cup) converts to 236.6 mL, the precise metric equivalent. Most metric recipes round to 240 mL for practical "1 cup" measures, accepting a small (~1.4%) overage for tidier numbers. For baking, the 3 mL gap rarely matters.
1.5 fl oz, standard cocktail shot
- Volume 1.5 fl oz
1.5 fl oz is 44.4 mL, the standard US "shot" size. European cocktail recipes typically reference 4 cl (40 mL) or 4.5 cl (45 mL) shots, slightly less than the US standard. The difference shifts a typical 3-shot cocktail's alcohol content by ~10-15% between US and European pour standards.
Frequently asked questions
How do I convert fluid ounces to milliliters?
Multiply by 29.5735 for the exact answer, or by 30 for a quick estimate (within 1.5%). So 12 fl oz × 29.5735 = 354.88 mL (close to the well-known 355 mL soda-can size). For bartending, the exact factor matters because pour sizes are often 0.5 oz increments and the small differences add up across multiple drinks.
Is a US cup 240 mL or 250 mL?
A US cup is exactly 236.59 mL, but 240 mL is the conventional rounding for recipe purposes. The "metric cup" (used in Australia and New Zealand) is 250 mL, intentionally a clean number. UK and Canadian recipes vary, check the source. For baking precision, weigh ingredients in grams; for casual cooking, any of the three "cup" sizes get you close enough.
How do I read a 750 ml bottle in fl oz?
750 mL × 0.033814 = 25.36 fl oz. The standard wine bottle size, about 5 standard 5-oz pours, or 4 generous 6-oz pours. Common related sizes: 187 mL (split / quarter bottle), 375 mL (half bottle), 500 mL (some specialty bottles), 750 mL (standard), 1.5 L (magnum), 3 L (jeroboam).
Why don't US recipes use grams instead of fluid ounces?
Cultural inertia, the US never fully adopted metric, and US-cookbook traditions standardized on volumes (cups, tbsps, fl oz) decades before the food-science community embraced weight measures. Serious US bakers and most professional kitchens do use grams; consumer-level cookbooks lag. Weight is more accurate (a cup of flour can vary 20%+ by packing); for precision baking, switch to grams regardless of which country your recipe came from.