The short answer: 1 millilitre = 0.0338 fluid ounce. That single number is the whole conversion — multiply any amount in millilitres by 0.0338 and you have the amount in fluid ounces. It is an exact conversion between two units of volume in the US customary system, so there is no estimating, no density to look up and no ingredient that changes it. A millilitre of water, a millilitre of milk and a millilitre of stock are all 0.0338 fluid ounce.
Unlike a conversion between cups and grams, which depends on what is in the cup, this one has a single right answer. A millilitre is a defined volume and a fluid ounce is a defined volume, so the ratio between them is fixed by the definitions themselves. That makes it reliable in a way that ingredient conversions are not — and it means the table on this page is correct for every liquid, from water to cream to stock, without exception.
Conversion table
| Millilitres | Fluid ounces |
|---|---|
| 15 millilitres | 0.5072 fluid ounce |
| 30 millilitres | 1.0144 fluid ounces |
| 60 millilitres | 2.0288 fluid ounces |
| 100 millilitres | 3.3814 fluid ounces |
| 120 millilitres | 4.0577 fluid ounces |
| 250 millilitres | 8.4535 fluid ounces |
| 500 millilitres | 16.907 fluid ounces |
| 1000 millilitres | 33.814 fluid ounces |
Read the table in either direction. Going from millilitres to fluid ounces, multiply by 0.0338; going back, divide by 0.0338 or multiply by 29.5735. The middle rows are the ones recipes use most — 100 millilitres is 3.3814 fluid ounces, and 250 millilitres is 8.4535 fluid ounces. If your amount is not in the table, multiply it by 0.0338 and you have the answer. For a quick check: 1 millilitre is 0.0338 fluid ounce, 2 millilitres are 0.0676 fluid ounce, and 10 millilitres are 0.3381 fluid ounce.
Worked examples
A roast chicken gravy that needs 60 millilitres. The recipe calls for 60 millilitres and your jug is marked in fluid ounces. That is 2.0288 fluid ounces — pour to that line and you have the right amount. If you double the recipe for a crowd, you need 120 fluid ounces, which is 4.0577 fluid ounces. The conversion itself never changes with the ingredient: whether the roast chicken gravy uses milk, water or melted butter, 60 millilitres is always 2.0288 fluid ounces. What changes is only the weight, never the volume.
A small batch, halved. A overnight oats recipe makes too much, so you halve it. The original uses 120 millilitres; halved, that is 60 millilitres, which is 2.0288 fluid ounces. Small amounts are where conversion errors hurt most, because a 10% error in a small amount of liquid is a bigger share of the recipe. When the halved amount is awkward, measure it in fluid ounces — the finer unit gives you a cleaner number.
Baking, where precision matters. A cake batter that needs 120 millilitres of milk has no room for guessing: that is 4.0577 fluid ounces. In baking, liquid is a structural ingredient, and a 10% error changes the crumb. If your recipe gives the liquid in fluid ounces and your cups are in millilitres, convert before you start, not while the oven is heating. And if the recipe also gives a weight in grams, use the weight — it is the most accurate measure of all.
How the conversion works
The US millilitre is defined as 1 ml, and the fluid ounce is defined as 29.5735 ml. Divide the first by the second and you get 0.0338 — that is the whole derivation, and it is why the conversion is exact rather than approximate. No kitchen experiment was needed to establish it; the units were defined this way, so the ratio follows from the definitions. That is also why the same factor appears in every reliable conversion chart: there is only one right answer, and every source that uses US customary units agrees on it.
The one thing to check is which millilitre your recipe means. This page uses the US customary millilitre throughout. A metric cup is 250 ml, an imperial cup is 284 ml, and older recipes sometimes use a 'cup' that means whatever cup the writer had in the cupboard. If a recipe from outside the US gives an amount that looks wrong after converting — a cake with far too much liquid, a soup that is far too thin — the cup is the first suspect. Convert the recipe to grams once, write the grams on the recipe card, and the question never comes up again.
Rounding deserves a note too. The exact factor is 0.0338 to four decimal places, and the full value runs further (1.00 ml divided by 29.57 ml). For everyday cooking, rounding to two or three significant figures is fine: a 1% rounding error is invisible in a soup and barely noticeable in a cake. But round only at the end. If you round the factor and then multiply by a large amount, the rounding error grows with the amount — so keep the full factor through the calculation and round the answer, not the factor.
Volume is not weight
A conversion between two volume units is the same for every ingredient, but a conversion between volume and weight is not — and confusing the two is the most common conversion mistake in cooking. A cup of all-purpose flour weighs about 120 g spooned and levelled (King Arthur Baking), a cup of granulated sugar about 198 g, a cup of butter about 227 g, a cup of milk about 244 g (USDA), and a cup of honey about 336 g. All of those weights are approximate, because they depend on how the ingredient is measured: flour is spooned and levelled, brown sugar is packed at about 213 g a cup, and honey is poured.
Flour weight is the most disputed conversion in baking. King Arthur Baking lists 120 g per cup spooned and levelled, while other sources quote 125 g, 130 g and up to 142 g for a scooped cup. We use the King Arthur spooned-and-levelled value as primary, and the gap is a warning: if you scoop flour instead of spooning and levelling it, you can add 20 g or more per cup, which is enough to make a cake dry. Granulated sugar carries a smaller dispute — King Arthur lists 198 g per cup and the USDA rounds it to 200 g, a difference of rounding rather than a real disagreement. When a recipe matters, verify with a kitchen scale: weigh the ingredient instead of measuring it by volume, and every dispute on this page disappears.
Small amounts and precision
Small measures are where conversions matter most, because the same absolute error is a bigger share of a small amount. A teaspoon that is off by a quarter is a 25% error; a cup that is off by a quarter is a 6% error. That is why baking recipes give leavening, salt and spices in teaspoons and tablespoons rather than cups: the small unit is the precise one. Use proper measuring spoons, not cutlery — a teaspoon from the drawer can hold anywhere from 3 ml to 7 ml, which makes the conversion meaningless. Level every spoon with a knife, and do not pack a spoon measure unless the recipe says packed. For amounts under a teaspoon, a pinch is about a sixteenth of a teaspoon and a dash is about an eighth, but those are estimates, not conversions, and they belong in seasoning, never in baking. If a recipe needs half a teaspoon and you only have a teaspoon measure, fill it halfway and level it — or weigh it, because a scale reads half a teaspoon of baking soda at about 2.3 g without any conversion at all.
Frequently asked questions
How many fluid ounces are in 1 millilitre?
Exactly 0.0338 fluid ounce. Multiply any number of millilitres by 0.0338 to get fluid ounces — for example, 120 millilitres is 4.0577 fluid ounces. The conversion is exact because both units are defined volumes in the US customary system.
What is 100 millilitres in fluid ounces?
3.3814 fluid ounces. Multiply 100 by 0.0338: 100 × 0.0338 = 3.3814. This is a common recipe amount — a third of a cup of cream, a few spoonfuls of oil — so it is worth knowing it is a straight multiplication with no special case.
Is a US millilitre the same as a metric or imperial millilitre?
Not always, and this is the biggest trap in unit conversion. This page uses the US millilitre (1 ml). A metric cup is 250 ml, an imperial cup is 284 ml, a US pint is 473 ml while an imperial pint is 568 ml, and an Australian tablespoon is 20 ml against the US 14.79 ml. If your recipe comes from outside the US, check which system it uses before converting — the factor on this page is correct for US measures only.
Can I use a kitchen scale instead of converting?
For liquids, often yes. A kitchen scale removes volume conversion entirely if the recipe gives grams, and for water-based liquids 1 ml weighs about 1 g, so millilitres and grams are nearly interchangeable. But the shortcut fails for fats and syrups: a cup of olive oil weighs about 216 g, not 237 g, and a cup of honey about 336 g. Use the scale when the recipe gives weights, and use this conversion when the recipe gives volumes.
Does temperature change the conversion?
No, not in any way that matters in a kitchen. Liquids expand slightly when heated, so a cup of boiling stock is a fraction of a percent larger in volume than a cup of cold stock, but the difference is far smaller than ordinary measuring error. Measure liquids at room temperature where you can, and never worry about temperature when converting between volume units.