A level teaspoon of baking soda weighs about 5 to 6 grams. King Arthur Baking lists 1/2 teaspoon at 3 g, which puts the grams in a teaspoon of baking soda at 6 g, while the Arm & Hammer label lists 1/8 teaspoon at 0.6 g, which works out to 4.8 g per teaspoon.
| Amount | Baking soda (King Arthur, 6 g per tsp) |
|---|---|
| 1/8 tsp | 0.8 g |
| 1/4 tsp | 1.5 g |
| 1/2 tsp | 3 g |
| 1 tsp | 6 g |
| 1 tbsp | 18 g |
Why the grams in a teaspoon of baking soda vary
Baking soda is a fine, dense powder, so you'd expect one clean answer. The gap comes from two places.
First, rounding. Nutrition labels round small servings, so Arm & Hammer's 0.6 g for 1/8 teaspoon could be a little higher or lower in reality. Multiply a rounded number by eight and the error grows.
Second, packing. Baking soda settles in the box and can pack tightly. A spoon pressed into a firm box holds more than a spoon filled from loose powder. Lumps add weight too.
So the honest answer is a range: about 5 to 6 g per teaspoon. The table above uses King Arthur Baking's figure because it's what many bakers work from.
Why a gram of baking soda matters
Most recipes use baking soda in tiny amounts, often 1/2 teaspoon or 1 teaspoon for a whole batch. It's strong stuff. It reacts with acidic ingredients like buttermilk, yogurt, brown sugar or natural cocoa to make the bubbles that lift your bake.
Too little and your muffins come out dense. Too much and you can get a soapy or metallic taste, plus extra browning. Because the amounts are so small, a heaped spoon can be a big percentage error. For more on this, see how to measure small ingredients without guessing.
Scaling a recipe makes this even trickier. Halve a recipe that calls for 1/2 teaspoon and you need 1/4 teaspoon, about 1.5 g. Halve it again and you're at 1/8 teaspoon, which is less than a gram.
How to measure baking soda
- Stir the baking soda in the box to break up any lumps.
- Dip your measuring spoon in so it's overfilled.
- Level it with a straight edge.
- Whisk it into the dry ingredients so it spreads evenly.
Baking soda vs baking powder
They look alike but aren't the same, and they don't weigh the same either. King Arthur Baking lists baking powder at 4 g per teaspoon, compared to 6 g for baking soda. Baking powder already contains its own acid, so it doesn't need an acidic ingredient to work. Don't swap one for the other unless a recipe tells you how.
Freshness matters as well. An open box can lose strength over time, especially if it's stored near moisture. To test it, stir a pinch into a spoonful of vinegar. If it fizzes right away, it's still good for baking.
Common mistakes to watch for: grabbing the wrong box, using a heaped spoon, and measuring over the mixing bowl, where a spill goes straight into the batter.
A practical tip for tiny amounts: a MeasureMate digital measuring spoon scoops and weighs in one step, and its display reads in 0.1 g steps, so you can see the difference between 3 g and 3.5 g. Press tare to zero it before you scoop. It switches between grams, ounces and other units if your recipe uses something else.
Quick questions
How many grams is 1/2 teaspoon of baking soda?
About 3 g, according to King Arthur Baking's chart.
How many grams are in a tablespoon of baking soda?
About 14.4 to 18 g, since a tablespoon holds 3 teaspoons.
Does baking soda weigh more than baking powder?
Per teaspoon, yes. King Arthur Baking lists baking soda at 6 g and baking powder at 4 g.
Weights based on the King Arthur Baking ingredient weight chart and the Arm & Hammer baking soda label.