What Can I Use Instead of Icing Sugar? Low-Carb Baking Swaps

Quick answer: The best low-carb alternative to icing sugar is a powdered erythritol and stevia blend, which you can swap 1:1 in buttercream, glazes, cheesecakes and dusting. No powdered sweetener in the cupboard? Blitz a granulated blend in a dry blender until it's as fine as flour. For the rest of your baking, match the swap to the sugar the recipe asks for: a granulated blend for caster or granulated sugar, and a brown blend for soft brown sugar.

Most baking recipes in the UK use one of three sugars: caster or granulated, icing sugar, or soft brown sugar. Each one does a slightly different job, so the trick to good low-carb baking isn't finding one magic sweetener. It's choosing the right texture for each job. This guide walks you through every common swap, shows how much to use, and explains what changes in the oven so your bakes come out the way you expect.

Which sugar substitute is best for baking?

There isn't a single best option, because the sugar in a recipe isn't only there for sweetness. It affects texture, colour, moisture and how smooth a frosting feels. The easiest approach is to replace like with like.

Caster and granulated sugar

For sponges, cookies, muffins, crumbles and anything else made with caster or granulated sugar, use a granulated erythritol and stevia blend. Our Granulated Erythritol & Stevia Blend looks and feels like sugar and is designed to swap 1:1, so you can keep the recipe's quantities as they are. Erythritol on its own is noticeably less sweet than sugar. The small amount of stevia in a blend makes up the difference, which is why blends are easier to bake with than pure erythritol.

Caster sugar is simply finer than granulated, so it creams into butter more quickly. If a recipe relies on creaming butter and sugar until pale and fluffy, give the granulated blend a few extra minutes of beating, or pulse it briefly in a blender first to make it finer.

Icing sugar

Icing sugar matters most in recipes that never go in the oven: buttercream, glacé icing, cream cheese frosting, whipped cream and no-bake cheesecakes. There's nothing to dissolve the crystals, so a granulated sweetener leaves a sandy, crunchy texture. That's where a powdered sweetener comes in. Our Powdered Erythritol & Stevia Blend has a fine, soft texture like icing sugar and replaces it 1:1.

Soft brown sugar

Light and dark soft brown sugar bring a caramel flavour and a slightly chewy texture to cookies, flapjacks and spiced bakes. A plain white sweetener will still sweeten these, but the bake will taste flatter. Our Brown Erythritol & Stevia Blend has a golden colour and caramel flavour and is made to replace brown sugar 1:1.

How much to use

All three blends below are designed to swap 1:1 for the sugar they replace. Always weigh rather than using cups or spoons, because powdered sweeteners are much fluffier than granulated ones, so a spoonful weighs less.

The recipe says	Swap it for	How much	Best for
Caster sugar	Granulated erythritol and stevia blend	Same weight (100g for 100g)	Sponges, cupcakes, shortbread
Granulated sugar	Granulated erythritol and stevia blend	Same weight	Cookies, crumbles, muffins, sauces
Icing sugar	Powdered erythritol and stevia blend	Same weight	Buttercream, glazes, frostings, whipped cream, dusting
Light or dark soft brown sugar	Brown erythritol and stevia blend	Same weight	Cookies, flapjacks, gingerbread, crumble toppings
Demerara (for topping)	Granulated or brown blend	A light sprinkle	A crunchy finish on muffins and crumbles

Sweetness is personal. Many people find frostings made 1:1 a touch sweeter than they remember, so it's worth starting with about three-quarters of the amount, tasting, then adding more.

Icing sugar alternatives for frostings, glazes and dusting

This is where the right sweetener makes the biggest difference. Here's how to get the best results from a powdered blend in each kind of topping.

Buttercream

Beat soft unsalted butter on its own for two to three minutes until pale, then add the sifted powdered blend a few spoonfuls at a time. Finish with a splash of double cream or milk and vanilla. Sifting matters more than usual, because powdered sweeteners can clump in the bag. A small pinch of salt rounds out the flavour.

Glacé icing and drizzles

Mix the powdered blend with a few drops of water or lemon juice at a time until it coats the back of a spoon. Erythritol can recrystallise as it dries, so a drizzle may set with a slightly frosted look rather than a glossy one. Drizzle it onto completely cool bakes, close to serving, for the smoothest finish.

Whipped cream and cream cheese frosting

A powdered blend dissolves quickly in cold recipes, which makes it ideal for sweetening whipped cream or a cream cheese frosting. Add it once the cream starts to thicken. Some cream cheese frostings use only a small amount of sweetener. For a simple version, try our keto cream cheese icing recipe.

Royal icing and dusting

Royal icing made with a powdered sweetener will set, but it tends to be more fragile than the sugar version and can develop a light crystalline bloom after a day or so. Pipe decorations close to when you need them. For a snowy dusting on brownies, sponges or our keto mince pies, sift the powdered blend over the top once the bake is completely cold, because it soaks into a warm surface and disappears.

Can you make your own icing sugar substitute?

Yes. If you have a granulated sweetener but no powdered version, you can make your own in a couple of minutes:

1. Make sure your blender jug, spice grinder or coffee grinder is completely dry. Any moisture will make the powder clump.
2. Add the granulated sweetener. Smaller batches of 100g to 200g grind more evenly.
3. Blitz in short bursts for 30 to 60 seconds, until it looks like flour.
4. Leave it for a minute so the fine dust settles before you open the lid.
5. Sift it and store it in an airtight jar. If it clumps later, blitz it again.

Shop-bought icing sugar sometimes contains a little anti-caking agent, and you'll see online tips suggesting cornflour for the same job. Cornflour is almost pure starch, so leave it out if you're keeping things low-carb. A quick re-blitz does the same job.

Brown sugar alternatives

Brown sugar's flavour comes from molasses, which also makes it moist and a little sticky. A brown erythritol and stevia blend gives you the golden colour and caramel notes. It won't add quite the same stickiness, so recipes that depend on it, such as chewy cookies or flapjacks, benefit from a few small tweaks:

• Chewy cookies: chill the dough for 30 minutes and take the cookies out while the centres still look slightly underdone. They firm up as they cool.
• Flapjack-style bars: press the mixture firmly into the tin and leave it to cool completely before cutting.
• Gingerbread and spiced bakes: warm spices such as ginger, cinnamon and mixed spice go a long way towards the deep, rounded flavour you'd get from dark muscovado.

If you only have a white granulated blend, it will still work in these recipes. You'll simply lose some of the caramel flavour and colour.

What changes when you bake with a sugar substitute?

Erythritol-based sweeteners measure like sugar, but they don't behave exactly like sugar in the oven. Knowing what to expect avoids most disappointments.

• Colour: sugar caramelises and helps bakes turn golden. Erythritol doesn't caramelise in the same way, so low-carb bakes can look paler when they're done. Go by the recipe's timing and a skewer test rather than colour alone, or brush with beaten egg for a golden top.
• Moisture: sugar holds on to water, which keeps sponges soft. Bakes made with erythritol can be slightly drier and firmer, especially the next day. Avoid overbaking and store them in an airtight tin.
• Spread: cookies made with erythritol often spread less than sugar cookies. Flatten the dough balls a little before baking if you want a thinner cookie.
• Crystallisation: erythritol can recrystallise as it cools, which can make sauces, custards, caramel and glazes turn grainy. A powdered blend dissolves more readily and helps.
• Cooling taste: erythritol can leave a slight cooling sensation, most noticeable in uncooked recipes. Blends with stevia, plus vanilla, cocoa, spices or citrus, help balance it.
• Yeast: yeast can't feed on erythritol. Use a recipe written for low-carb yeasted baking rather than swapping it into a standard bread recipe.

Low-carb bakes often use alternative flours, too. If you're also replacing wheat flour, follow a recipe developed for that combination, because sugar and flour swaps affect each other. For a wider look at every sweetener option, including monk fruit, stevia and xylitol, read our guide to keto sugar substitutes compared.

Frequently asked questions

What can I use instead of icing sugar?

A powdered erythritol and stevia blend is the closest low-carb match. Our Powdered Erythritol & Stevia Blend replaces icing sugar 1:1 in buttercream, glazes and cheesecakes. If you only have a granulated sweetener, blitz it in a dry blender until it is as fine as flour.

Can I use granulated sweetener instead of icing sugar?

In cakes, cookies and other bakes where the sweetener dissolves in the oven, usually yes. In uncooked recipes such as buttercream, glacé icing or whipped cream, granulated sweetener stays crunchy and tastes gritty, so grind it to a powder first or use a powdered blend.

How do I convert granulated sugar to powdered sugar?

Put granulated sweetener in a completely dry high-speed blender or spice grinder and blitz it in short bursts for 30 to 60 seconds, until it looks like flour. Let the dust settle before opening the lid, then sift it and store it in an airtight jar.

Which sugar substitute is best for baking?

Match the substitute to the sugar in the recipe: a granulated erythritol and stevia blend for caster or granulated sugar, a powdered blend for icing sugar and a brown blend for soft brown sugar. Blends labelled as 1:1 let you keep the recipe's quantities the same.

What can I use instead of brown sugar in baking?

A brown erythritol and stevia blend, such as our Brown Erythritol & Stevia Blend, swaps 1:1 for light or dark soft brown sugar. It has a golden colour and caramel flavour, which suits cookies, flapjacks, crumbles and spiced bakes.

Bake with the right swap

Choosing a sugar substitute for baking is easiest when you match it to the sugar it replaces. Use the Powdered Erythritol & Stevia Blend for icing sugar, the Granulated Erythritol & Stevia Blend for caster and granulated sugar, and the Brown Erythritol & Stevia Blend for soft brown sugar. Weigh everything, expect slightly paler bakes, and taste your frostings as you go.