How Many Grams Is 2/3 Cup of Butter? | Exact Conversions

2/3 cup of butter weighs approximately 151 grams (5.3 ounces) using the standard US conversion where 1 cup equals 227 grams.

You pull out the butter for a cookie recipe, and the wrapper shows tablespoon lines but nothing for 2/3 cup. Your dry measuring cups have 1/4, 1/3, 1/2, and 1 cup — no 2/3 in sight. It’s a common spot to get stuck.

The good news is the answer is simple and consistent across most baking resources. 2/3 cup of butter converts to roughly 151 grams, or about 5.3 ounces. That number is based on the standard US cup-to-gram ratio that 1 cup of butter equals 227 grams.

The Simple Answer: 151 Grams Per 2/3 Cup

Butter’s weight is consistent because it’s a dense, solid fat at room temperature. Unlike flour or sugar, the same volume of butter will weigh roughly the same every time — as long as it’s packed without air gaps.

The math is straightforward. One cup of butter is 227 grams, so two-thirds of that comes out to 151 grams. Divide 227 by 3 and multiply by 2, and you get 151.3 grams. Most recipes round this to 151 grams without issue.

In ounces, 2/3 cup of butter is about 5.3 ounces. That lines up with the standard US stick of butter, which is 113 grams or 4 ounces per half cup. A single stick won’t get you to 2/3 cup — you need one full stick plus about one-third of a second stick.

Why Cup Measurements Create Confusion

The biggest source of confusion around butter measurement is that not all cups are the same size across the world. A US cup is 240 milliliters, while a metric cup — used in Australia and parts of Europe — is 250 milliliters. That difference changes the weight.

If you’re following a recipe written in the US, the baker expects the 240 mL cup standard. International recipes may use the 250 mL metric cup, which gives a higher gram count. A metric cup of butter weighs about 250 grams instead of 227 grams.

That 23-gram difference per cup adds up. For 2/3 cup, it would mean roughly 166 grams instead of 151 grams. This is why knowing which cup standard your recipe uses makes a difference for precise baking.

What About Salted Versus Unsalted Butter

Salted and unsalted butter weigh the same gram-for-gram. The salt content affects flavor, not density. You can use the same conversion for either type. Just be aware the recipe’s salt balance may shift if you swap one for the other.

Where 2/3 Cup Butter Sits On The Conversion Chart

Having a full conversion chart makes scaling recipes easier. The relationship between cup sizes and grams is linear, so you can calculate any measurement once you know that 1 cup equals 227 grams. International conversions sometimes use a slightly higher gram-per-cup ratio — Taste.com.au’s 2 cups butter grams chart, for example, lists 2 cups as approximately 500 grams, reflecting the metric cup standard common in Australia.

This table assumes the US cup standard (240 mL per cup). If you’re using a metric cup or Australian tablespoon system, the numbers shift upward by about 10 percent. For most cookie and cake recipes, the difference of a few grams won’t break the bake, but pastry and high-hydration doughs benefit from precision.

How To Measure 2/3 Cup Of Butter Accurately

Without a kitchen scale, you need a method that avoids air pockets and uneven packing. Butter is forgiving compared to flour, but volume measurements still have room for error. Here are reliable approaches.

1. Use the water displacement method. Fill a liquid measuring cup with 2/3 cup of cold water, then add butter pieces until the water level reaches 1 1/3 cups. Drain the water and you have exactly 2/3 cup of butter by volume.
2. Use tablespoon marks on the wrapper. A standard US stick of butter has tablespoon markings along the wrapper. One cup equals 16 tablespoons, so 2/3 cup equals about 10 2/3 tablespoons. That’s one full stick (8 tablespoons) plus 2 2/3 tablespoons from the second stick.
3. Cut based on stick fractions. One stick is 1/2 cup. For 2/3 cup, you need one full stick (1/2 cup) plus an additional 1/6 cup. Since 1/3 cup is 5 1/3 tablespoons, half of that is about 2 2/3 tablespoons. Cut a second stick at the 2 2/3 tablespoon line.

These methods work best with cold butter straight from the fridge. Softened butter compresses differently and can give you slightly less than the expected weight. If the recipe needs room-temperature butter, let it come up to temperature after measuring.

Why Bakers Prefer Weight Over Volume

Professional bakers consistently choose weight measurements over volume for one reason: consistency. A cup of butter measured by packing can vary by several grams depending on temperature, air incorporation, and how firmly you press it into the cup.

A kitchen scale eliminates that variability. Per KitchenAid’s 2/3 cup butter milliliters converter, the same volume of butter translates to about 160 milliliters in metric volume measurements. Having both weight and volume numbers helps when a recipe is written in one system and your equipment supports the other.

The scale wins every time for pastry, laminated doughs, and any recipe where butter-to-flour ratio matters. For casual cookie baking, the wrapper marks or water displacement method will get you close enough for a great result.

What About Grams Per Stick Of Butter

A standard US stick of butter is 1/2 cup, which equals 113 grams. Two sticks make 1 cup (227 grams). Four sticks make 1 pound (454 grams). Memorizing these benchmarks helps you do quick conversions without looking up a chart.

The Bottom Line

2/3 cup of butter weighs 151 grams or 5.3 ounces under the US cup standard. If your recipe uses metric cups, expect about 166 grams instead. A kitchen scale is the most reliable tool, but water displacement and wrapper markings work well in a pinch.

For detailed baking or scaling a recipe up or down, running the math against the type of cup used in your recipe’s country of origin gives you the most accurate result every time.