Convert a recipe’s butter measurement into the equivalent amount of oil.
How it works
Butter is roughly 80% fat plus water and milk solids, while oil is 100% fat, so less oil is needed for the same fat content: oil = butter × 0.75. 1 cup of butter converts to about 0.75 cups of oil.
What this does not include
3/4 is a widely used kitchen approximation, not an exact figure — swapping oil for butter also changes texture and moisture in ways this ratio alone doesn’t capture, especially in baked goods that rely on butter’s structure (like flaky pastry).
How to use this calculator
- Enter the amount of butter your recipe calls for.
Why does oil need less volume than butter for the same fat content?
Butter is only about 80% fat by weight (the rest is water and milk solids), while oil is essentially pure fat, so a smaller volume of oil delivers the same amount of fat.
Does this substitution work for every type of baked good?
Not equally well — recipes relying on butter’s solid structure at room temperature (like pie crusts or laminated doughs) generally don’t substitute well with liquid oil, while many cakes and quick breads handle the swap fine.
Should I adjust other ingredients when substituting oil for butter?
Some bakers add a small amount of extra liquid or reduce other fats slightly to compensate for butter’s water content, though this varies by recipe and isn’t part of this calculator’s simple ratio.
