Baking Soda ↔ Baking Powder Substitute

They're not interchangeable 1:1 — baking soda is about 3-4x stronger than baking powder. Here's the right ratio.

Reference table

Baking soda	Baking powder equivalent
1/4 tsp	3/4 tsp
1/2 tsp	1 1/2 tsp
1 tsp	3 tsp (1 tbsp)
2 tsp	6 tsp (2 tbsp)

Why they're not the same

Baking soda is pure sodium bicarbonate and needs an acid (buttermilk, lemon juice, brown sugar) in the recipe to activate. Baking powder already contains its own acid, so it works without one — but it's weaker per teaspoon, which is why the substitute ratio isn't 1:1. Swapping without adjusting the amount will leave baked goods flat or give them a metallic aftertaste.