1 fluid ounce = 0.0313 quart. Cups, spoons, pints and litres are all measures of the same thing — volume — and this page converts between two of them. The factor is fixed by definition, not measured in a kitchen, so it is the same for every ingredient, every recipe and every brand of measuring cup. What follows is the full table for the amounts you actually cook with, worked examples from real recipes, and the mistakes that catch people out even when the maths is right.
This is one of the conversions that comes up again and again once you start cooking from recipes written in different countries. A British cookbook, an American blog and a metric website can all describe the same amount of liquid in three different units, and the dish is the same dish. The table below covers the amounts that actually appear in recipes, from a single spoonful to a full pot, so you can find your amount without doing the arithmetic yourself.
Conversion table
| Fluid ounces | Quarts |
|---|---|
| 1 fluid ounce | 0.0313 quart |
| 2 fluid ounces | 0.0625 quart |
| 4 fluid ounces | 0.125 quart |
| 6 fluid ounces | 0.1875 quart |
| 8 fluid ounces | 0.25 quart |
| 12 fluid ounces | 0.375 quart |
| 16 fluid ounces | 0.5 quart |
| 32 fluid ounces | 1 quarts |
Read the table in either direction. Going from fluid ounces to quarts, multiply by 0.0313; going back, divide by 0.0313 or multiply by 32. The middle rows are the ones recipes use most — 6 fluid ounces is 0.1875 quart, and 12 fluid ounces is 0.375 quart. If your amount is not in the table, multiply it by 0.0313 and you have the answer. For a quick check: 1 fluid ounce is 0.0313 quart, 2 fluid ounces are 0.0625 quart, and 10 fluid ounces are 0.3125 quart.
Worked examples
Checking a measuring jug. Jugs are not always honest. Pour 4 fluid ounces of water into the jug — that should read 0.125 quart on the quarts scale. If it reads noticeably more or less, trust the fluid ounces: measuring cups and spoons are made to a standard, while cheap jugs are often printed a few percent out. A jug that is wrong by 5% will put 5% too much liquid in every cake, soup and sauce you make with it, which is enough to notice.
Working from a video recipe. The cook on screen measures 4 fluid ounces and your set only has a quart measure. That is 0.125 quart — pause the video, count them out, and carry on. Video recipes are the worst for mixed units, because the cook never stops to convert for you. Keep this page open on your phone while you cook and the pause button becomes your conversion chart.
A recipe written in the other system. You find a pickling brine recipe from a metric cookbook that lists 0.5 quart, but your measuring cups are marked in fluid ounces. That is 16 fluid ounces — a familiar measure again. This is the most common reason people look this conversion up mid-cook: one recipe, two measuring systems, and dinner in an hour. Convert the whole recipe to one system before you start, write the converted amounts on the page, and you will not have to do the arithmetic with wet hands.
How the conversion works
The US fluid ounce is defined as 29.5735 ml, and the quart is defined as 946.3529 ml. Divide the first by the second and you get 0.0313 — 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 fluid ounce your recipe means. This page uses the US customary fluid ounce 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 0.0313 to four decimal places, and the full value runs further (29.57 ml divided by 946.35 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
Is a US fluid ounce the same as a metric or imperial fluid ounce?
Not always, and this is the biggest trap in unit conversion. This page uses the US fluid ounce (29.5735 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.
How many fluid ounces are in 1 quart?
32 fluid ounces — the reverse of the main conversion. Divide the number of quarts by 0.0313, or multiply by 32. For example, 128 fluid ounces is 4 quarts. Use the reverse direction when a metric recipe gives you quarts and your cups are in fluid ounces.
How do I convert fluid ounces to quarts without a calculator?
Multiply by 0.0313; for a quick mental estimate, round the factor to a friendly number and accept a small error. If the factor is larger than 1, break the amount into whole units and fractions — for example, convert 2 fluid ounces and a half fluid ounce separately and add them. If the factor is smaller than 1, remember that one quart is 32 fluid ounces, which is often easier to picture. For anything that matters, a phone calculator or the table on this page is faster and more accurate than mental maths mid-recipe.