Butter Calculator

Background.

An American recipe asks for a stick and a half of butter, and the butter in your fridge is a 250 g block with no markings. Or a British recipe wants 225 g and all you have are sticks. Butter is the one ingredient that US cooks measure by volume and count while most of the world weighs it, and moving between the two needs to know what a cup of butter actually weighs.

The US system rests on a single fact: a stick is a quarter of a pound. Everything else on the wrapper follows from it — 4 ounces, 8 tablespoons, half a cup — and four sticks make the one-pound box. Since the avoirdupois pound is defined as exactly 453.59237 g, a stick is 113.4 g, a tablespoon 14.17 g and a cup two sticks, 226.8 g. Enter any amount in any of the eight units and every other unit comes back at once.

The USDA's nutrition database rounds those portions a little differently: a tablespoon of 14.2 g, a stick of 113 g and a cup of 227 g. Each figure is sensible on its own, but they do not agree with each other — eight of those tablespoons make 113.6 g, two of those sticks make 226 g. You can choose either basis. The quarter-pound basis keeps every wrapper identity exact, and the USDA basis matches USDA nutrition figures; the gap is never more than about half a percent.

Alongside the conversions you get the milkfat and water in the amount, from USDA's analysis of salted butter, and the least fat a product of that weight must contain to be sold as butter in the United States.

What is butter calculator?

Butter is a water-in-oil emulsion: droplets of water and a small amount of milk solids held in a continuous phase of milkfat. US law has defined it since 1923, in 21 U.S.C. 321a, as a food made only from milk or cream, with or without salt and coloring, containing not less than 80% milkfat by weight. The international Codex standard for butter sets the same 80% minimum and adds limits of 16% water and 2% milk solids-not-fat. USDA's analytical figures for salted butter, FoodData Central entry 173410, put the average at 81.11 g of fat and 16.17 g of water per 100 g, which leaves 2.72 g for milk solids and salt.

How to use this calculator.

1. 01Enter the amount and choose the unit it is measured in: sticks, tablespoons, teaspoons, cups, pats, grams, ounces or pounds. There is no target unit to pick; all eight come back together.
2. 02Keep the quarter-pound basis for everyday cooking and baking. Switch to the USDA basis only when you are matching a quantity to a USDA nutrition label or database entry built on its 113 g stick and 14.2 g tablespoon.
3. 03For a recipe written in grams, weigh the butter if you can. If you can only cut it, use the stick or tablespoon figure and the markings on the wrapper; one tablespoon line is about 14 g.
4. 04Check the milkfat line when fat content matters, as in pastry, shortbread or laminated dough. If your butter's label gives a higher fat percentage, multiply the gram figure by that percentage instead.

The formula.

Grams = amount × k, where k is the weight of one unit on the basis you chose; every other unit is grams ÷ its own k. On the quarter-pound basis the constants come from the exact pound of 453.59237 g: a stick is 453.59237 ÷ 4 = 113.398 g, a cup is two sticks, 226.796 g, a tablespoon an eighth of a stick, 14.175 g, and a teaspoon a third of a tablespoon, 4.725 g. The ounce is exactly 28.349523125 g, and the pat is USDA's 5 g, a square an inch across and a third of an inch thick. On the USDA basis the stick, cup and tablespoon are 113 g, 227 g and 14.2 g as published, with the teaspoon again a third of the tablespoon; ounces, pounds and pats are unchanged. Composition is three proportions of the gram figure: fat = grams × 0.8111, legal minimum fat = grams × 0.80 and water = grams × 0.1617. The volume units assume solid butter cut from a stick or packed firmly into a measure. Melted, softened-and-whipped or tub butter takes up a different volume for the same weight, so the cup and tablespoon figures do not apply to it.

A worked example.

Frequently asked questions.

References& sources.

1. [1]U.S. Department of Agriculture, Agricultural Research Service. FoodData Central, SR Legacy entry FDC ID 173410, "Butter, salted"; retrieved 30 July 2026 through the FoodData Central REST API endpoint /v1/food/173410. The source of every composition and portion figure on this page: total lipid (fat) 81.11 g per 100 g (580 data points); water 16.17 g per 100 g (7 analytical samples, range 15.8 to 16.61 g); and the household portions 1 pat (1 inch square, 1/3 inch high) = 5 g, 1 tablespoon = 14.2 g, 1 cup = 227 g, 1 stick = 113 g. Those four portion weights are the USDA mass basis offered on the page, and their mutual inconsistency is documented in the basis note.
2. [2]United States Code, Title 21, Section 321a — "Butter" defined (enacted 4 March 1923, 42 Stat. 1500); retrieved 30 July 2026 from the Cornell Legal Information Institute's reproduction of the US Code. Quoted verbatim for the statutory floor this page reports as the legal-minimum milkfat figure: butter is "the food product usually known as butter, and which is made exclusively from milk or cream, or both, with or without common salt, and with or without additional coloring matter, and containing not less than 80 per centum by weight of milk fat, all tolerances having been allowed for."
3. [3]National Institute of Standards and Technology. NIST Special Publication 811, 2008 edition — Guide for the Use of the International System of Units (SI). Table B.8, avoirdupois mass: the pound is exactly 453.59237 g and the ounce exactly 28.349523125 g. Every ounce and pound figure on this page comes from these values, as does the whole quarter-pound-stick basis: a stick is 453.59237 / 4 = 113.3980925 g, a tablespoon 453.59237 / 32, a cup 453.59237 / 2, and the teaspoon is derived as a third of the tablespoon using the exact 1 tbsp = 3 tsp identity from Table B.6.
4. [4]King Arthur Baking Company. Ingredient Weight Chart, current revision; retrieved 30 July 2026. Cited as an independent publisher confirming the stick identity set this page is built on: "Butter — 8 tablespoons (1/2 cup): 4 ounces / 113 grams", which ties the stick, the eight tablespoons, the half cup and the four ounces together in one published line, with the gram figure rounded to 113 exactly as USDA's portion table has it.