288 g of baking soda is 1 cup. Like salt, baking soda is dense and heavy per cup, but nobody measures it by the cup: a whole cup of baking soda would ruin any recipe it touched. The figure is here as a reference and as the basis for the tablespoon and teaspoon weights, which are the ones that actually matter. One teaspoon of baking soda is 4.8 g, and that is the unit that decides whether a cake rises or tastes of soap.
All figures on this page are approximate, and they come from King Arthur Baking, measured spooned and levelled. When a recipe has to work the first time, verify with a kitchen scale.
Conversion table
| Cups | Grams of baking soda |
|---|---|
| 1/4 cup | 72 g |
| 1/3 cup | 96 g |
| 1/2 cup | 144 g |
| 2/3 cup | 192 g |
| 3/4 cup | 216 g |
| 1 cup | 288 g |
| 1 1/2 cups | 432 g |
| 2 cups | 576 g |
| 3 cups | 864 g |
| 4 cups | 1152 g |
Quick reference: 100 g of baking soda is about 0.35 cups, and 50 g is about 0.17 cups. All figures are approximate; verify with a kitchen scale when it matters.
Method and source
The figure on this page comes from King Arthur Baking, measured spooned and levelled. Sodium bicarbonate; needs an acid to activate. Leavening cakes, cookies and quick breads with acidic ingredients.
All results on this page are approximate. Ingredient weights vary with brand, humidity, temperature and how firmly you pack the cup, so when a recipe has to work the first time, weigh the ingredient on a kitchen scale and use the numbers here as a guide.
Worked examples
Buttermilk pancakes on a Sunday
A pancake recipe uses 5 g of baking soda, about 1 teaspoon, with 500 g of buttermilk. The acid in the buttermilk activates the soda, producing the bubbles that make the pancakes fluffy. If you doubled the soda, the pancakes would rise fast and then collapse, with a yellow tinge and a soapy taste.
A chocolate cake that relies on soda
A chocolate cake with cocoa powder and buttermilk calls for 7 g of baking soda, about 1 1/2 teaspoons. Natural cocoa is acidic, so it activates the soda, and the reaction also darkens the crumb to a deep reddish brown. Too little soda and the cake is dense; too much and it tastes metallic.
Cookies that spread just right
A cookie recipe uses 2.4 g of baking soda, half a teaspoon, for a batch that makes two dozen cookies. That small amount is enough to give the cookies their spread and their chew. Baking soda is one of the few ingredients where half a teaspoon more or less is visible in the finished bake.
Practical guidance
Dry powders and leavening agents are measured spooned and levelled, never heaped and never scooped from the container. A heaped tablespoon of baking soda can be double the intended amount, and that much extra leavening leaves a soapy, metallic taste and a collapsed crumb. Dip a dry spoon into the container, fill it, then level it with the back of a knife. Keep leavening in airtight containers away from humidity, and replace baking powder every six months once opened, because stale powder is the most common silent cause of flat cakes.
Scaling is straightforward once you know the cup weight. Doubling a recipe that calls for 288 g of baking soda means measuring 576 g, or 2 cups, and tripling it means 864 g, or 3 cups. Halving is just as easy: half a cup is 144 g. The key is to scale every ingredient by the same factor, because changing one ingredient without changing the others throws the recipe out of balance. A cake scaled by half still needs half the flour, half the sugar, half the butter and half the baking soda, not just half of one of them. If you are scaling a recipe by an awkward factor, like two thirds, weigh the baking soda rather than trying to measure two thirds of a cup in a jug, because the jug markings are not precise enough for fractions of a cup.
When should you weigh baking soda instead of measuring it? Whenever the recipe has to work the first time, and whenever the amount is large. A kitchen scale costs less than a single failed cake, and it removes the biggest source of variation in home cooking: the way ingredients pack into a cup or a spoon. Put the bowl on the scale, press tare, and add the baking soda until the display shows the number you need. There is nothing to wash afterwards except the bowl, and the result is the same every time. For small amounts, a level spoon is accurate enough, and for liquids, a jug is fine, but for anything where precision matters, the scale is the tool to reach for.
Storage. Airtight container, cool and dry, up to 6 months once opened.
- Level every spoon with the back of a knife.
- Test old baking soda in vinegar before using it.
- Replace opened baking soda every six months.
Frequently asked questions
How much baking soda is in a teaspoon?
One level teaspoon of baking soda weighs about 4.8 g, and one tablespoon is 18 g. A quarter of a teaspoon, a common amount in small recipes, is about 1.2 g.
Can I use baking powder instead of baking soda?
Not directly. Baking soda needs an acid to activate, while baking powder contains its own acid. As a rough guide, use three times as much baking powder as baking soda, but the result will be different, and the recipe may taste slightly bitter.
What happens if I use too much baking soda?
The bake rises quickly and then collapses, and it tastes soapy and metallic, sometimes with a yellow or brown discolouration. Too much soda is worse than too little, because an under-risen cake is still edible while a soapy one is not.
Does baking soda go stale?
Yes. It absorbs moisture and odours from the air, and once opened it loses strength within about six months. Test it by dropping half a teaspoon into a little vinegar: it should fizz vigorously. If it barely bubbles, replace it.
Why do recipes pair baking soda with buttermilk or vinegar?
Baking soda is alkaline, and it needs an acid to produce carbon dioxide, the gas that lifts a batter. Buttermilk, yogurt, vinegar, lemon juice and natural cocoa are all acids that do the job. Without an acid, baking soda barely reacts at all.
Common mistakes to avoid
The most common mistake with dry powders is using a heaped spoon instead of a level one, which can double the amount of a powerful ingredient like baking soda. The second is scooping the spoon straight from the container, which packs the powder down and adds weight. The third is using a damp spoon, because moisture makes powders clump and stick, and the measurement becomes unreliable. The fourth mistake is confusing baking soda and baking powder, which look identical but behave very differently: soda needs an acid, powder does not, and swapping them will change whether a bake rises at all. Finally, do not keep leavening agents in a humid kitchen without a sealed container, because they absorb moisture and lose their strength, and a cake made with stale baking powder will not rise no matter how carefully you measure it.