One cup of buttermilk weighs 245 g, poured, according to the USDA. Buttermilk is cultured milk with a tangy flavour and a pourable consistency, and its cup weight of 245 g is almost identical to yogurt's — both are fermented milks, and both weigh a little more than plain milk because of the cultures and the slightly thicker body. The figure matters for pancakes, biscuits, fried chicken and soda bread, where buttermilk is measured by the cup and the weight decides the acidity and the moisture. All weights on this page are approximate; the USDA lists cultured buttermilk at about 245 g per cup, while the King Arthur chart rounds it to 227 g, so verify with a scale when precision matters.
Buttermilk: weight and measurement table
The table below gives the weight of buttermilk in every measure you will use, from a teaspoon up to 2 cups, all derived from the USDA figure of 245 g per cup, poured. Every figure is approximate — poured is a technique, not a machine setting — so when the recipe matters, weigh the ingredient on a kitchen scale instead.
| Amount | Weight (approx.) |
| --- | --- |
| 1 teaspoon | 5.1 g |
| 1 tablespoon | 15.3 g |
| 1/4 cup (4 tbsp) | 61.2 g |
| 1/3 cup | 81.7 g |
| 1/2 cup (8 tbsp) | 122.5 g |
| 3/4 cup (12 tbsp) | 183.8 g |
| 1 cup (16 tbsp) | 245 g |
| 2 cups | 490 g |
| 100 g | 0.4 cups |
There are 3 teaspoons in a tablespoon and 16 tablespoons in a cup, so you can move between any of these measures by multiplying or dividing. If a recipe calls for 100 g and you only have measuring cups, that is about 0.4 cups. Keep the cups to grams converter open while you cook and you will never need to do the arithmetic in your head.
What is Buttermilk?
Buttermilk is tangy cultured milk that tenderises batters and activates baking soda. Milk is inoculated with lactic acid bacteria, which ferment the lactose into lactic acid, giving the milk its tang and its slightly thicker body. It is used for pancakes, biscuits, fried chicken and ranch dressing, and it brings two things to a dish: acidity, which reacts with baking soda to give lift, and tenderness, because the acid breaks down gluten and keeps the crumb soft. It should be refrigerated and used within 2 weeks of opening. A tangy smell is normal — buttermilk is already cultured, so discard it only if it smells sharply off or shows mould.
How to measure Buttermilk correctly
Buttermilk is measured poured, and the method matters more than most cooks realise. For dry ingredients, spoon the ingredient into the measure with a smaller spoon, letting it fall loosely, then sweep a knife across the top to level it — never dip the measuring cup into the bag, because dipping compresses the ingredient and adds up to 20 percent. For liquids, pour into a liquid measuring jug and read the level at eye height, or weigh directly into the bowl, which is the most accurate method of all. The USDA figure used on this page is 245 g per cup, and it is the figure the site's converters use, so the numbers here and the numbers in the tool always agree. Confidence in this figure is high.
A note on the published figures
USDA lists cultured buttermilk at about 245 g per cup; King Arthur rounds it to 227 g.
Worked examples
Buttermilk pancakes for a weekend
A pancake batter for four uses 2 cups of buttermilk — 490 g — with 2 cups of flour, 2 eggs and 2 teaspoons of baking soda. The weight matters because the soda and the acid must balance: 490 g of buttermilk against 8 g of baking soda gives a complete reaction, with no soda left over to taste soapy. Weighing the buttermilk keeps the balance exact, and it also lets you scale the recipe — a half batch needs 245 g, and a double batch needs 980 g. The batter is rested for 5 minutes, then cooked on a medium heat until bubbles appear, and the pancakes come out tall, fluffy and tangy.
Buttermilk biscuits for breakfast
A biscuit recipe uses 1 cup of buttermilk — 245 g — with 2 cups of flour, a tablespoon of butter and a teaspoon of baking soda. The weight is useful because biscuit dough is sensitive to liquid: 245 g of buttermilk against 240 g of flour gives a dough that just comes together, while a tablespoon too much makes it sticky and a tablespoon too little leaves it dry and crumbly. Weighing the buttermilk keeps the dough right, and the dough is handled as little as possible — overworking it develops gluten and makes the biscuits tough. The biscuits are baked for 15 minutes, until golden, and split open while still warm.
Buttermilk fried chicken
A fried chicken marinade uses 2 cups of buttermilk — 490 g — to soak four chicken pieces overnight. The weight matters because the marinade needs to cover the chicken completely: 490 g is enough to submerge four pieces in a bowl, while a cup too little leaves the top pieces dry. The buttermilk's lactic acid tenderises the chicken gently, and its thickness helps the flour coating cling, which is why buttermilk fried chicken has a craggier, crunchier crust than chicken marinated in plain milk. The chicken is dredged in seasoned flour, fried at 180 C until golden, and rested for 5 minutes before serving.
The acid that lifts biscuits
Buttermilk's job in baking is acidity, and its acidity is what makes biscuits rise and pancakes fluffy. The lactic acid in buttermilk reacts with baking soda to release carbon dioxide, and that gas is the lift. The ratio matters: a recipe calling for 1 cup of buttermilk and 1 teaspoon of baking soda is balanced at about 245 g of acid against 4.8 g of soda, and that balance is what gives a complete reaction with no soda left over. Too little buttermilk and the soda is left unreacted, tasting soapy; too much and the batter turns overly tangy and can collapse. The same acid also tenderises the crumb, because it breaks down gluten strands and keeps the bake soft — which is why buttermilk biscuits are more tender than milk biscuits, and why buttermilk pancakes are fluffier. The practical rule is to use buttermilk whenever a recipe calls for it, and if you have none, to make a substitute: 1 tablespoon of lemon juice or white vinegar per cup of milk, rested for 5 minutes, gives soured milk with a similar acidity. It is not identical — soured milk lacks buttermilk's body — but it works in most recipes. And when you measure buttermilk, weigh it: 245 g per cup, 15.3 g per tablespoon.
What to use instead
If you run out of buttermilk, these are the tested substitutes from our substitution data, with the ratio and the case where each one does not work. Use the ratio by weight where it is given, and check the warning before you commit the batter.
Buttermilk to Milk and lemon juice: 1 tbsp lemon juice per cup of milk, rested 5 minutes. Do not use plain milk — without acid, baking soda will not activate and the bake can taste soapy.
Buttermilk to Milk and vinegar: 1 tbsp white vinegar per cup of milk, rested 5 minutes. Do not use plain milk — without acid, baking soda will not activate and the bake can taste soapy.
Buttermilk to Yogurt: 1:1 (thin with a little water if very thick). Do not use plain milk — without acid, baking soda will not activate and the bake can taste soapy.
Buttermilk to Sour cream: 1:1 (thin with a little water). Do not use plain milk — without acid, baking soda will not activate and the bake can taste soapy.
The golden rule for any substitution is to match the job, not just the ingredient: a substitute that works in a sauce may fail in a cake, because the two recipes ask different things of the ingredient. When in doubt, use a recipe written for the substitute rather than adapting one written for the original.
Storage
Refrigerate; use within 2 weeks. That is the headline, but the details matter. Store buttermilk in an airtight container, away from heat, light and strong smells — dry ingredients absorb odours readily, and a bag of flour stored next to the spices will taste of them within a week. Label the container with the date you opened it, so you know how long it has been there, and check it before you bake: if it smells off, tastes bitter, or shows any sign of moisture or insects, discard it. Buying in smaller quantities and using it promptly is better than buying in bulk and storing it for a year, because every ingredient loses flavour with time, even the ones that never truly go bad.
Frequently asked questions
How many grams is 1 cup of buttermilk?
One cup of buttermilk weighs 245 g, poured, according to the USDA. The King Arthur chart rounds it to 227 g, but the USDA value is more accurate. One tablespoon weighs 15.3 g.
How many tablespoons of buttermilk are in 100 g?
There are about 6.5 tablespoons in 100 g of buttermilk (100 divided by 15.3 is 6.5). A standard 500 ml carton holds about 490 g, which is roughly 32 tablespoons or 2 cups.
What can I use instead of buttermilk?
Mix 1 tablespoon of lemon juice or white vinegar into 1 cup of milk and rest it for 5 minutes. Plain yogurt thinned with a little water also works 1:1. Do not use plain milk on its own in a recipe that relies on baking soda — without acid, the soda will not activate.
Can I freeze buttermilk?
Yes. Freeze it in tablespoon portions in an ice cube tray, then transfer the cubes to a bag. Thaw in the fridge and shake well before using. Frozen buttermilk works perfectly in baking, though its texture is not ideal for drinking.
How long does buttermilk last once opened?
About 2 weeks in the fridge, sealed tightly. Buttermilk is already cultured, so a tangy smell is normal — discard it only if it smells sharply off, tastes bitter, or shows mould.
Related pages
If you cook with this ingredient regularly, these pages will help: the cups to grams converter for any amount, the ingredient density lookup for the full table of 120 ingredients, the Buttermilk cups to grams page for cup conversions, the Buttermilk grams to cups page for working backwards from grams, and the Buttermilk tablespoons to grams page for spoon measures. You may also want Milk, Yogurt.