Butter ↔ Oil Substitute Calculator

Butter is about 80% fat and 20% water; oil is 100% fat. That's why the swap isn't 1:1 — here's the right ratio.

Quick reference

Butter	Oil equivalent
1 tbsp	2 1/4 tsp
1/4 cup	3 tbsp
1/2 cup	6 tbsp (3/8 cup)
1 cup	3/4 cup

When not to substitute

Oil works well in quick breads, muffins, and brownies where butter's role is mainly moisture and fat. Skip the swap in recipes where butter is creamed with sugar for structure and lift (most cakes and cookies) — oil can't trap air the way solid butter can, so texture will suffer.