There are 32 fluid ounces in a US quart, and about 40 fluid ounces in an Imperial quart. Both answers are correct, and which one you need depends on which quart the recipe means. An American quart holds 32 US fluid ounces, which is 946 ml, and a British quart holds 40 Imperial fluid ounces, which is 1,136 ml. The two quarts share a name and nothing else, and mixing them up will leave you short by nearly a cup. This page gives you both tables, the examples, and the rule for telling them apart.
The conversion table
| Quarts | US fluid ounces | Imperial fluid ounces | Cups | Pints | Millilitres |
|---|---|---|---|---|---|
| 1/4 quart | 8 fl oz | 10 fl oz | 1 cup | 1/2 pint | 237 ml US / 284 ml Imp |
| 1/2 quart | 16 fl oz | 20 fl oz | 2 cups | 1 pint | 473 ml US / 568 ml Imp |
| 3/4 quart | 24 fl oz | 30 fl oz | 3 cups | 1 1/2 pints | 710 ml US / 852 ml Imp |
| 1 quart | 32 fl oz | 40 fl oz | 4 cups | 2 pints | 946 ml US / 1,136 ml Imp |
| 1 1/2 quarts | 48 fl oz | 60 fl oz | 6 cups | 3 pints | 1,419 ml US / 1,705 ml Imp |
| 2 quarts | 64 fl oz | 80 fl oz | 8 cups | 4 pints | 1,893 ml US / 2,273 ml Imp |
| 3 quarts | 96 fl oz | 120 fl oz | 12 cups | 6 pints | 2,839 ml US / 3,409 ml Imp |
| 4 quarts | 128 fl oz | 160 fl oz | 16 cups | 8 pints | 3,785 ml US / 4,546 ml Imp |
The millilitre figures are rounded to the nearest whole number. The US column is based on 29.57 ml per fluid ounce, and the Imperial column on 28.41 ml.
Worked example 1: a quart of stock for a soup
An American recipe calls for 1 quart of stock, and your jug is marked in fluid ounces. One US quart is 32 fluid ounces, so pour the stock to the 32-ounce line. If you are halving the recipe, you need half a quart, which is 16 fluid ounces, or 2 cups. The conversion is simple, but the usual mistake is to measure 40 fluid ounces, because someone remembers that a quart is 40 ounces — which is true of an Imperial quart, and wrong for an American one. Always check the recipe's origin before you pour.
Worked example 2: a British recipe and an American jug
An old British cookbook asks for 1 quart of milk, and you measure it in an American jug marked in fluid ounces. An Imperial quart is 40 Imperial fluid ounces, which is 1,136 ml, and 1,136 ml is 38.4 US fluid ounces. If you measure 32 US fluid ounces, you will be short by 6.4 fluid ounces — about 80 percent of a cup. For a soup, that does not matter. For a custard, it does. The fix is to convert through millilitres: an Imperial quart is 1,136 ml, so measure 1,136 ml, or 38 US fluid ounces, and ignore the quart marks on the jug.
Worked example 3: a quart carton and its label
A carton of milk is labelled 1 quart, and the metric label says 946 ml. Nine hundred and forty-six divided by 32 is 29.6, which is the US fluid ounce, so the carton is a US quart. A British carton labelled 1.136 litres would be an Imperial quart, and it would hold 40 Imperial fluid ounces. Checking a label is a good way to confirm which quart you are dealing with: if the millilitres divided by the fluid ounces is about 29.6, it is a US quart, and if it is about 28.4, it is Imperial.
Method and source
A US quart is defined as a quarter of a US gallon, which is 32 US fluid ounces, or 946.35 millilitres. An Imperial quart is defined as a quarter of an Imperial gallon, which is 40 Imperial fluid ounces, or 1,136.52 millilitres. The two fluid ounces are also different: a US fluid ounce is 29.57 ml, and an Imperial fluid ounce is 28.41 ml. That means the two systems do not scale the same way: a US quart holds fewer fluid ounces than an Imperial quart, but each US fluid ounce is larger. The American system is built on powers of two — 2 pints to a quart, 4 quarts to a gallon — while the Imperial system is built on 40 fluid ounces to a quart, which is why the two quarts are so different.
Practical guidance
Remember the two anchor numbers: a US quart is 32 fluid ounces, and an Imperial quart is 40 fluid ounces. If a recipe is American, use 32. If it is British and old, use 40 Imperial fluid ounces, or 1,136 ml. If the recipe gives millilitres, use those directly and skip the quarts. Buy a jug marked in both fluid ounces and millilitres, and use it for liquids; for dry ingredients, weigh them. When you scale a recipe, convert to millilitres first, do the multiplication, and convert back at the end, because millilitres are the same everywhere and the maths stays exact.
Frequently asked questions
How many fluid ounces are in 1 quart?
There are 32 US fluid ounces in 1 US quart, and 40 Imperial fluid ounces in 1 Imperial quart. Use 32 if the recipe is American, and 40 if it is British. The difference is about 190 ml.
How many fluid ounces are in half a quart?
There are 16 US fluid ounces in half a US quart, and 20 Imperial fluid ounces in half an Imperial quart. Half a US quart is also 2 cups, 1 pint, and about 473 ml.
How many quarts are in 32 fluid ounces?
There is 1 US quart in 32 US fluid ounces. Thirty-two fluid ounces is the definition of a US quart, so if a recipe gives an amount in fluid ounces that adds up to 32, you can measure it as a quart instead.
Is a quart 32 or 40 ounces?
Both, depending on the system. A US quart is 32 US fluid ounces, and an Imperial quart is 40 Imperial fluid ounces. The two fluid ounces are also different sizes, so a British quart holds 1,136 ml and an American quart holds 946 ml.
How many fluid ounces are in 2 quarts?
There are 64 US fluid ounces in 2 US quarts, and 80 Imperial fluid ounces in 2 Imperial quarts. Two US quarts is also 8 cups, 4 pints, and about 1.89 litres.
How many cups are in a quart?
There are 4 US cups in a US quart, and about 4.8 US cups in an Imperial quart. A US quart is 4 cups, which is the simplest conversion in the American system, and the one to memorise first.
The quart is where US and imperial measures part ways: a US quart holds 32 fluid ounces, while an imperial quart holds 40. Old British cookbooks and some Commonwealth recipes use the imperial quart, so a recipe that says one quart of stock means 40 ounces in that system and 32 in the American one. Check the recipe's origin before you measure.