Volume

Fluid Ounces to Milliliters

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fl oz ml
Formula

Multiply fluid ounces by 29.5735

1 US fluid ounce equals 29.5735 ml exactly, derived from the US gallon (3785.41 ml ÷ 128 fl oz per gallon). 1 imperial fluid ounce equals 28.4131 ml exactly, from the imperial gallon (4546.09 ml ÷ 160 fl oz per gallon). The two gallons differ because the US adopted the older Queen Anne gallon while the UK switched to the imperial gallon in 1824. The 4% spread persists in every fluid-oz-based unit (cup, pint, quart, gallon).

About fluid ounces to milliliters

Fluid ounces and millilitres both measure liquid volume, but the unit 'fl oz' itself has two definitions. The US fluid ounce equals 29.5735 ml; the imperial (UK) fluid ounce equals 28.4131 ml.

The two differ by about 4%, which sounds small but matters for cocktails, medication doses, and cosmetic-product labeling. American recipes, beverage containers, and the FDA use US fl oz. UK recipes, Australian recipes, and Commonwealth labeling use imperial fl oz.

ConvertBuddy uses the US fl oz definition (29.5735 ml) as default since it dominates online recipe content. Convert with care when sourcing recipes from UK or AU cookbooks, or when reading European cosmetic-product fill volumes.

Common conversions

fl oz ml
1 fl oz 30 ml
2 fl oz 59 ml
4 fl oz 118 ml
6 fl oz 177 ml
8 fl oz 237 ml
10 fl oz 296 ml
12 fl oz 355 ml
16 fl oz 473 ml
20 fl oz 591 ml
24 fl oz 710 ml
32 fl oz 946 ml
64 fl oz 1893 ml
Also: Milliliters to Fluid Ounces

When you need this

Cocktail bartending

Cocktail recipes list jiggers and fl oz. Bar tools sold in EU and Asian markets are marked ml. A standard 1.5 fl oz pour is ~44 ml; a 2 fl oz pour is ~59 ml. Convert to set up consistent pours across mixed-marking equipment.

Pediatric medication dosing

Many liquid medications in the US ship with fl-oz markings on the bottle but dosing instructions in ml on the syringe. Misreading the unit can double or halve the dose.

Skincare product purchasing

US-market skincare lists ml and fl oz; European-market identical SKUs list only ml. Convert to confirm size match before buying same-product variants across regions.

Coffee recipe ratios

Pour-over and espresso recipes from US-based baristas use fl oz; international specialty coffee uses ml or grams. Convert to lock in extraction ratios when following recipes across markets.

Wine and spirits import labeling

Customs and excise paperwork sometimes lists shipment volumes in fl oz while local distributors use litres or ml. Convert to verify shipment quantity matches purchase orders.

FAQ

How do I convert fl oz to ml?

Multiply US fl oz by 29.5735. So 1 fl oz = 29.6 ml, 8 fl oz = 236.6 ml (a standard US cup), 16 fl oz = 473 ml (a US pint). For imperial fl oz multiply by 28.4131 instead.

Is a US fl oz the same as a UK fl oz?

No — they differ by about 4%. US fl oz = 29.57 ml; imperial (UK) fl oz = 28.41 ml. ConvertBuddy uses US fl oz by default. Check the recipe origin to know which to apply.

How many ml in 1 fl oz?

1 US fl oz equals 29.5735 ml, typically rounded to 30 ml in casual use. 1 imperial fl oz equals 28.4131 ml, typically rounded to 28 ml.

Why do US and UK fl oz differ?

The two countries use different gallon definitions. The US uses the Queen Anne gallon (3785.4 ml), pre-1824 English standard. The UK adopted the imperial gallon (4546.1 ml) in 1824 but the US never followed. Every fluid-oz-based unit inherits the discrepancy.

Are US fl oz and US cups related?

Yes — a US cup is exactly 8 US fl oz, or 236.59 ml. Older recipes sometimes blur cups and fl oz; modern usage keeps them distinct (cups for cooking, fl oz for beverages and pharmacy).

How does fl oz compare to a shot?

A US bar 'shot' is typically 1.5 fl oz (44 ml), sometimes 1 fl oz (30 ml) for whiskey or 2 fl oz (59 ml) for a 'double'. There is no legal definition — convention varies by establishment and country.

Why label cosmetics in fl oz?

FDA labeling rules require dual US-customary and metric volume on consumer products sold in the US. International brands print fl oz only for the US-market label; the EU/UK label of the same product shows only ml.

Is 100 ml about 3 fl oz?

Closely — 100 ml equals 3.38 US fl oz or 3.52 imperial fl oz. Both round comfortably to 'about 3.4 fl oz'. The TSA carry-on liquid limit of 3.4 fl oz / 100 ml derives from this almost-clean conversion.

Related converters

Milliliters to Fluid Ounces Cups to Milliliters Tablespoons to Milliliters Liters to Gallons