Is Baking Soda the Same as Bicarbonate of Soda? A UK Baking Guide
Yes. Baking soda is the American name for bicarbonate of soda. Both are pure sodium bicarbonate, so you can swap them spoon for spoon. Baking powder is different: it's bicarb mixed with a dry acid and a starch filler. Bicarb has 0g carbs, while baking powder has about 1.5g per level teaspoon, all from the starch.
At a glance
- 1:1use bicarbonate of soda wherever a US recipe says baking soda
- 3–4×bicarb is about three to four times stronger than baking powder
- 0gcarbs in bicarbonate of soda (CoFID)
- ~1.5gcarbs in a level teaspoon of baking powder
On this page
American recipes ask for baking soda. British ones ask for bicarbonate of soda, or just "bicarb". Add baking powder, cream of tartar and self-raising flour to the mix, and it's easy to reach for the wrong tub, which can mean flat pancakes, scones that taste soapy or a loaf that rises and then sinks.
This guide explains which names mean the same thing, how each raising agent works, how to swap one for another when you've run out, and how many carbs they add if you're baking keto.
Is baking soda the same as bicarbonate of soda?
Yes. Bicarbonate of soda is the British name and baking soda is the American name for the same ingredient: sodium bicarbonate, a fine white alkaline powder. In the UK you'll also see it sold as bicarb or bicarbonate of soda, and listed in ingredients as sodium bicarbonate or sodium hydrogen carbonate.
So if a US recipe asks for 1 teaspoon of baking soda, use 1 teaspoon of bicarbonate of soda. No conversion is needed, and the tub in the UK baking aisle is exactly what the recipe means.
The confusion usually comes from the next ingredient along. Baking soda and baking powder are easy to mix up, even in published recipes, so if a recipe seems to call for a surprisingly large amount, say a tablespoon in a single cake, check whether the writer meant baking powder.
Bicarbonate of soda and washing soda aren't the same. Washing soda (soda crystals) is sodium carbonate, a cleaning product. Never use it in food.
Bicarb, baking powder and cream of tartar
Here's how the common raising agents and their names line up:
| UK name | Also called | What it is | Needs an acid? |
|---|---|---|---|
| Bicarbonate of soda | Baking soda, bicarb, sodium bicarbonate | A pure alkali | Yes |
| Baking powder | Baking powder | Bicarb, a dry acid and a starch filler | No, it has its own |
| Cream of tartar | Potassium bitartrate | A dry acid from winemaking | It is the acid |
| Self-raising flour | Self-rising flour | Plain wheat flour with baking powder | No |
Ingredients vary by brand, so check the label. Self-raising flour is made from wheat, so it isn't used in keto baking.
How bicarb and baking powder work
Both are chemical raising agents. They make carbon dioxide gas, which forms tiny bubbles in a batter or dough. The bubbles expand in the oven's heat, and the bake sets around them, giving a light, open texture instead of a dense one.
Bicarbonate of soda needs an acid
Bicarb needs an acid and some moisture to give its full lift. Heat alone releases only about half its gas and leaves sodium carbonate behind, which is what tastes soapy. That's why recipes that use it always contain something acidic, such as:
- cider vinegar, white wine vinegar or lemon juice
- yoghurt, Greek yoghurt, soured cream or buttermilk
- natural cocoa powder (Dutch-processed cocoa has been treated to be less acidic)
- cream of tartar
The reaction starts as soon as the wet and dry ingredients meet, so bake a bicarb batter straight away. It's also strong: about three to four times stronger than baking powder, so recipes use it in small amounts, often just a quarter or half a teaspoon.
Baking powder brings its own acid
Baking powder is bicarbonate of soda that's already been mixed with a dry acid, plus a starch such as cornflour or rice flour. The starch keeps the powder dry in the tub so it doesn't react before you use it.
Because it carries its own acid, baking powder only needs moisture and heat. Most shop-bought baking powders react a little when they get wet, then give a second burst of gas in the oven. That makes them more forgiving if a batter has to sit for a few minutes.
Why some recipes use both
A recipe may use bicarb to balance an acidic ingredient such as yoghurt or lemon, and baking powder for most of the lift. The bicarb also encourages browning, so bakes with a little bicarb tend to colour more deeply.
Stir half a teaspoon of baking powder into 2 tablespoons of warm water, or a pinch of bicarb into a spoonful of vinegar. If it fizzes straight away, it's fine. If it barely bubbles, replace it.
How to swap one for the other
You can't swap bicarb and baking powder spoon for spoon, but you can make one do the job of the other in a pinch.
No baking powder? Make your own
For each 1 teaspoon of baking powder, mix ¼ teaspoon of bicarbonate of soda with ½ teaspoon of cream of tartar. BBC Good Food and King Arthur Baking both give this ratio. King Arthur also adds ¼ teaspoon of cornflour (cornstarch). The starch mainly keeps a stored batch dry, so you can leave it out if you're using the mix straight away. This homemade version reacts as soon as it gets wet, so get the bake into the oven quickly.
No cream of tartar either? Use ¼ teaspoon of bicarb plus ½ teaspoon of lemon juice or white vinegar for each teaspoon of baking powder, adding the acid with the wet ingredients.
No bicarb? Use more baking powder
King Arthur suggests 3 teaspoons of baking powder for each teaspoon of bicarb. It works, but that much baking powder can leave a slightly bitter taste, and it won't neutralise an acidic ingredient in the same way. It's best kept for emergencies.
Using a baking mix?
Our pancake and scone mixes already contain a raising agent, so you don't need to add any. The Keto Pancake Mix and Keto Scone Mix both list a baking powder made from monocalcium phosphate, rice flour and sodium bicarbonate in their ingredients. For pancakes or waffles you just add eggs and a milk alternative. For scones, you rub in cold butter, then add an egg and Greek yoghurt, as in our keto scones with jam and cream.
Free delivery is on orders over £30.
Why keto recipes use raising agents with vinegar
Keto bakes are made with ingredients such as ground almonds, coconut flour, psyllium husk and eggs instead of wheat flour. Without gluten to trap the gas, these doughs and batters are heavier, so raising agents matter even more.
That's why many keto bread recipes pair baking powder with a splash of cider vinegar. Our easy keto bread recipe uses 3 teaspoons (12g) of baking powder and 2 tablespoons of cider vinegar in one loaf. The vinegar adds extra acid, which helps any bicarbonate in the mix react fully and gives a lighter, more open crumb. Egg whites are slightly alkaline, and the vinegar balances them. You won't taste it once the loaf is baked.
A few more tips for keto bakes:
- Measure with proper spoons and level them off. A heaped spoon holds far more than a level one, and too much raising agent makes a bake rise fast and then collapse.
- Mix gently once the wet ingredients go in. Beating hard knocks out the bubbles the raising agent has just made.
- Don't leave a bicarb batter waiting. Get it into a preheated oven while it's still reacting.
New to low-carb baking? Our keto baking for beginners guide covers the main flours, binders and sweeteners, and how they behave.
Carbs in baking powder and bicarb
Bicarbonate of soda and cream of tartar contain no carbohydrate. Baking powder does, because of its starch filler. Here are the figures from the UK government's food composition data (CoFID):
| Raising agent | Carbs per 100g |
Level tsp |
Carbs per tsp |
|---|---|---|---|
| Bicarbonate of soda | 0g | 6g | 0g |
| Baking powder | 37.8g | 4g | 1.5g |
| Cream of tartar | 0g | – | 0g |
Source: CoFID 2021, foods 17-356 (bicarbonate of soda), 17-355 (baking powder) and 17-358 (cream of tartar). Teaspoon weights are from King Arthur Baking's ingredient weight chart. Carbohydrate excludes fibre, as on UK labels. Per-teaspoon figures are our own calculations.
Here's the maths. A level teaspoon of baking powder weighs about 4g, so it has 4 × 0.378 = about 1.5g of carbs. Spread across a whole bake, that's small. In our keto bread, 12g of baking powder adds 12 × 0.378 = 4.5g of carbs to the loaf, or about 0.4g per slice across 12 slices.
It's still worth counting if you track carbs closely, especially in small batches. CoFID's baking powder figure comes from one brand, and fillers vary, so check the nutrition panel on your tub. If you want to avoid the starch altogether, the homemade mix of bicarb and cream of tartar (without the cornflour) has no carbohydrate.
The cornflour in some baking powders is the same starch Americans call cornstarch. Our guide to whether cornflour is the same as cornstarch covers it, along with low-carb ways to thicken sauces.
Allergens: wheat in some baking powders
Bicarbonate of soda is a single ingredient, but baking powder isn't, and the filler varies from brand to brand. Many use cornflour or rice flour, but some use wheat flour.
Cereals containing gluten, including wheat, are one of the 14 allergens that must be emphasised in UK ingredients lists. If you avoid wheat or gluten, read the ingredients on your baking powder every time you buy it, as recipes can change. Self-raising flour is made from wheat.
Frequently asked questions
Can I use bicarbonate of soda instead of baking powder?
Only if you add an acid. Bicarbonate of soda is three to four times stronger than baking powder and has no acid of its own. For each teaspoon of baking powder, use a quarter of a teaspoon of bicarb plus half a teaspoon of cream of tartar, or half a teaspoon of lemon juice or vinegar, and bake straight away.
Is baking soda the same as baking powder?
No. Baking soda is bicarbonate of soda on its own, an alkali that needs an acid in the recipe to make it work. Baking powder is a ready-made mix of bicarbonate of soda, a dry acid and a starch filler, so it only needs moisture and heat. Don't swap them spoon for spoon.
Does baking powder have carbs?
Yes, a little. CoFID gives baking powder 37.8g of carbohydrate per 100g, all from the starch filler, so a level 4g teaspoon has about 1.5g. Bicarbonate of soda and cream of tartar have none. Spread across a whole loaf or batch, baking powder usually adds well under half a gram per portion.
Why do keto bread recipes add vinegar?
Almond, psyllium and egg white doughs are heavy, so they need all the lift they can get. A spoonful of cider vinegar adds extra acid, which helps any bicarbonate in the raising agent react fully and gives a lighter, more open crumb. Egg whites are slightly alkaline, and the vinegar balances them. You won't taste it once baked.
What happens if I use too much bicarbonate of soda?
Bicarb that hasn't met enough acid leaves a soapy or metallic taste. It can also make bakes brown too quickly, turn darker than expected or take on a greenish tinge, and they may rise fast and then sink. Use a proper measuring spoon, level it off and stick to the amount in the recipe.
Sources
- GOV.UK / Public Health England. Composition of Foods Integrated Dataset (CoFID) 2021. Carbohydrate per 100g for bicarbonate of soda (17-356), baking powder (17-355) and cream of tartar (17-358). Per-teaspoon and per-slice figures are our own calculations.
- BBC Good Food. Baking powder: what's in it and the homemade ratio of ½ tsp cream of tartar to ¼ tsp bicarbonate of soda.
- BBC Good Food. Plain flour cake recipes: bicarbonate of soda is three to four times stronger than baking powder, and too much gives a metallic or soapy flavour.
- King Arthur Baking. What's the difference between baking soda and baking powder?: substitution ratios.
- King Arthur Baking. Ingredient weight chart: baking powder 4g per teaspoon; baking soda 3g per half teaspoon.
- Food Standards Agency (GOV.UK). Allergen guidance for food businesses: cereals containing gluten as one of the 14 allergens.
- Groovy Keto product pages: Keto Pancake Mix and Keto Scone Mix: ingredients, preparation and nutrition.
