Cooking Oil Converter

Cooking oil conversions by volume and weight.

Density of common oils (grams per tablespoon):

• Olive oil: 13.5 g
• Coconut oil (liquid): 13.6 g
• Vegetable / canola oil: 13.6 g
• Butter: 14.175 g (one US stick is 4 oz, or 8 tablespoons)

1 cup, which is 16 tablespoons:

Two different conversions, and mixing them up is the whole problem. The boxes above convert by weight: 1 tablespoon of butter weighs 14.175 g, and 14.175 g of olive oil is 1.05 tablespoons. That is the right answer if you are weighing fat, counting calories, or scaling a recipe written in grams.

Baking substitution is a different question and gives a different number. Butter is only about 80% fat. The rest is water and milk solids, which is why the standard kitchen rule is:

• Butter to oil: use 3/4 the amount. 1 cup butter becomes 3/4 cup oil.
• Oil to butter: use 1 1/3 the amount. 1 cup oil becomes 1 1/3 cups butter.
• Coconut oil for butter: 1:1, because solid coconut oil creams in a way liquid oils cannot.
• Olive for vegetable oil: 1:1 in anything savoury. In a cake, expect to taste it.

Run the arithmetic and the 3/4 rule turns out to be slightly stingy on purpose. A cup of butter carries 182 g of fat, and matching that exactly would take 13.4 tablespoons of oil, closer to 5/6 of a cup than 3/4. Recipes call for the smaller amount because liquid oil coats flour more thoroughly than solid butter does, so a little less of it goes further. You lose something either way: butter creamed with sugar traps air, and no amount of oil will do that. Swap oil into a creamed-butter cake and you get a denser, moister crumb. Often a pleasant result, but not the same cake.

The other thing worth remembering is that oil is lighter than water. A cup weighs about 218 g where a cup of water is 237. So a recipe listing oil in grams and one listing it in cups are not interchangeable without the conversion, and eyeballing the swap in a bread dough is how hydration calculations go wrong.