The easiest baking soda substitute is baking powder: use 3 times as much baking powder by volume, which works out to about 2 times as much by weight. So 1/2 tsp of baking soda (3 g) becomes 1 1/2 tsp of baking powder (6 g).
| Baking soda in the recipe | Soda weight | Baking powder to use | Powder weight |
|---|---|---|---|
| 1/4 tsp | 1.5 g | 3/4 tsp | 3 g |
| 1/2 tsp | 3 g | 1 1/2 tsp | 6 g |
| 3/4 tsp | 4.5 g | 2 1/4 tsp | 9 g |
| 1 tsp | 6 g | 1 tbsp | 12 g |
Why the swap isn't one to one
Baking soda is much stronger than baking powder. Arm & Hammer describes it as about 3 to 4 times as strong, which is why recipes use so little of it, typically around 1/4 tsp per 1 cup of flour. Baking powder is baking soda with an acid already mixed in, so you need more of it to get the same lift.
The weight math looks odd at first. Why is it 3 times by volume but only 2 times by weight? Because the two powders weigh different amounts per spoon. The King Arthur Baking ingredient weight chart puts baking soda at 3 g per 1/2 tsp, or 6 g per tsp, and baking powder at 4 g per tsp. Three teaspoons of powder weigh 12 g, which is twice the 6 g of soda it replaces.
When a baking soda substitute works and when it doesn't
Swapping in baking powder works well in recipes where soda is the only leavener and the amount is small, like pancakes, muffins and quick breads. You'll usually get good rise.
Keep your expectations in check with these:
- Recipes with a lot of soda. A recipe calling for 1 tsp of soda would need 1 tbsp of powder. That much powder can change the flavor, so try it on a small batch first.
- Cookies. Texture and color can shift a little, so expect a cookie that's close to the original but not identical.
- Recipes that rely on soda to balance acid. Buttermilk, yogurt, brown sugar and natural cocoa all bring acid. The swap still rises, but the taste can come out a little tangier.
Going the other way: making baking powder from soda
If you're out of baking powder but have baking soda, you can mix your own. Arm & Hammer and Club House both give the same formula: 1 tsp of baking powder equals 1/4 tsp of baking soda plus 1/2 tsp of cream of tartar.
| Baking powder needed | Baking soda | Cream of tartar |
|---|---|---|
| 1 tsp (4 g) | 1/4 tsp (1.5 g) | 1/2 tsp (about 1.5 g) |
| 2 tsp (8 g) | 1/2 tsp (3 g) | 1 tsp (about 3 g) |
| 1 tbsp (12 g) | 3/4 tsp (4.5 g) | 1 1/2 tsp (about 4.5 g) |
Cream of tartar weighs about 3 g per tsp in USDA FoodData Central, and a store brand label lists 0.8 g per 1/4 tsp, so the weights above are rounded. Mix only what you need right before baking, since this homemade version reacts as soon as it gets wet.
No cream of tartar? Arm & Hammer also suggests 1/4 tsp of baking soda plus 1 tsp of lemon juice or vinegar for each teaspoon of baking powder. Count that juice or vinegar as part of the recipe's liquid, and expect a slight change in flavor.
Common mistakes
- Swapping one to one. The two aren't equal in strength, and Arm & Hammer warns that a straight swap can leave baked goods without proper lift. Always use the ratios above.
- Using old leaveners. Test baking soda by dropping a pinch into vinegar, and baking powder by dropping a pinch into hot water. Both should fizz right away.
- Heaping the spoon. At these tiny amounts, a rounded spoonful can throw the ratio off more than you'd guess.
Small amounts like 1.5 g are where weighing really helps. A MeasureMate digital measuring spoon scoops and weighs in one step and reads in 0.1 g steps, so you can see exactly when you've hit 1.5 g of soda or 6 g of powder. Press tare to zero the reading before each ingredient.
Quick questions
Can I use baking soda instead of baking powder?
Yes, but not on its own. Use 1/4 of the amount of baking powder called for and add an acid, like cream of tartar, lemon juice or vinegar.
Is bicarbonate of soda the same as baking soda?
Yes. Bicarbonate of soda, bicarb and baking soda are all names for sodium bicarbonate, so the amounts in this guide apply to all of them.
Weights based on the King Arthur Baking ingredient weight chart, USDA FoodData Central, a store brand cream of tartar label, and the Arm & Hammer and Club House substitution guides.