1 tablespoon of baking soda weighs 18 g. Baking soda is dense and heavy per tablespoon, and it is one of the few ingredients where a tablespoon is actually too much for most recipes: a whole tablespoon of baking soda would ruin any normal batch of baking. The tablespoon figure is here as a reference, and the useful numbers are the teaspoon at 4.8 g and the half teaspoon at 2.4 g.
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.
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.
Conversion table
| Amount | Grams of baking soda |
|---|---|
| 1 teaspoon | 6 g |
| 1 tablespoon | 18 g |
| 2 tablespoons | 36 g |
| 3 tablespoons | 54 g |
| 1/4 cup (4 tablespoons) | 72 g |
| 1/3 cup | 96 g |
| 1/2 cup (8 tablespoons) | 144 g |
| 3/4 cup (12 tablespoons) | 216 g |
| 1 cup (16 tablespoons) | 288 g |
One tablespoon is one sixteenth of a cup, so every figure above is simply the cup weight divided by 16, rounded to one decimal place. All figures are approximate; verify with a kitchen scale when it matters.
Three real kitchen examples
A large batch of cookies for a bake sale
A cookie recipe making four dozen cookies uses 1 tablespoon of baking soda, 18 g, for the whole batch. That is a large amount, and it is right for a large batch, because the soda needs to leaven a lot of dough. Level the spoon carefully, because a heaped tablespoon can be 22 g, which is enough to leave a soapy taste.
Buttermilk pancakes for a crowd
A pancake recipe serving eight uses 2 teaspoons of baking soda, about 9.6 g, which is two thirds of a tablespoon. The acid in the buttermilk activates the soda, and the pancakes rise fast. Cook them straight away, because the reaction starts as soon as the soda meets the buttermilk.
A chocolate cake that relies on soda
A chocolate cake recipe uses 1 1/2 teaspoons of baking soda, about 7.2 g, with natural cocoa and buttermilk. The soda reacts with the acid in both, and the reaction darkens the crumb to a deep reddish brown. Too much soda and the cake tastes metallic; too little and it is dense.
Getting it right in your kitchen
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 with tablespoons is easy once you know the weight of one spoon. To measure 100 g of baking soda, count out about 5.6 tablespoons, and for 50 g, about 2.8 tablespoons. Halving a recipe that calls for 4 tablespoons means using 2 tablespoons, or 36 g, and doubling it means 8 tablespoons, or 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. For large amounts, switch to a cup measure or a scale: counting out 16 tablespoons is slow and error-prone, and a cup is faster and more accurate.
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.
- A teaspoon of baking soda is 4.8 g.
- Test old baking soda in vinegar before using it.
Frequently asked questions
How many grams is a tablespoon of baking soda?
One tablespoon of baking soda weighs 18 g, and one teaspoon is 4.8 g. A quarter of a teaspoon, a common amount in small recipes, is about 1.2 g.
Why is a tablespoon of baking soda so heavy?
Baking soda is a dense, fine powder that packs tightly with very little air between the particles. A tablespoon of it weighs 18 g, against 7.5 g for a tablespoon of flour, which is a light, fluffy powder.
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.
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 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, 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.
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.