Converting a sugar recipe to honey — quantities, liquid, leavening and oven temperature
The traditional cup is 240 ml, the Australian cup is 250 ml.
Sugars pack to very different densities, so the cup measure changes with the type.
If you have kitchen scales, entering grams sidesteps the packing-density question entirely.
Honey's water content sets both how much you need and how much liquid to hold back.
Leave at 0 if the recipe has no free liquid to reduce — you'll still get the figure to subtract from somewhere.
Set to 0 for a stovetop or no-bake recipe.
Why less honey than sugar. Granulated sugar is granules with air between them; honey is a liquid that fills the cup completely. A 240 ml cup holds about 200 g of sugar but roughly 340 g of honey. Honey is also part water, so not all of that mass is sugar. Matching the sugar in the recipe therefore takes roughly two-thirds of a cup of honey per cup of sugar.
Why the honey matters. Water content is the figure that drives this whole calculation, and it varies more than most people expect: across 284 Australian samples the mean was 16.7%, but the range ran from 13.6% to 22.4%. A drier honey supplies more sugar per gram and brings less water to the recipe; a wetter one does the reverse. Water content also sets honey's density, so it changes the gram-to-millilitre conversion too. If you have a refractometer, your own reading beats any average here.
Why the liquid comes down. The water riding along in the honey is real liquid the recipe didn't ask for, so the same amount comes out of the water or milk. If you reduce a flavoured liquid instead, be aware you're also removing some of its flavour.
Why baking soda. Honey is acidic — typically pH 4.2, where granulated sugar is neutral — and that acidity interferes with the leavening the recipe was balanced for. Baking soda is a pure base and neutralises it directly. The standard figure is ¼ teaspoon (about 1.25 g) per cup of honey used.
Baking soda is not baking powder. Powder is a pre-balanced package — bicarbonate, its own acid, and starch — formulated to neutralise itself. It has nothing spare to spend on the honey. So if your recipe calls for baking powder, leave that quantity exactly as written and add the soda as well. There's a second reason beyond simple neutralising: unopposed honey acid starts reacting with the powder's bicarbonate in the bowl, at room temperature, wasting gas that was meant to arrive during the bake. The soda mops up that acid first and keeps the powder's release on schedule.
The one case for holding back is when honey is replacing an acidic ingredient that the recipe's own baking soda was there to balance — swapping honey for molasses, for instance. Soda with no acid left to react with is what produces a soapy, metallic taste and a yellowed crumb.
Why the oven drops. Sucrose is a non-reducing sugar and doesn't brown until it breaks down at about 160 °C. Honey is already mostly free fructose and glucose, and fructose starts caramelising around 110 °C — so a honey version browns earlier and can be dark outside before it's cooked through. Roughly 14 °C (25 °F) off the dial, and a little longer in the oven, puts it back.
Why the type of sugar matters. A cup is a measure of volume, and sugars fill it very differently: about 200 g of white granulated, 225 g of caster, but only 125 g of icing sugar to the same cup. Brown sugar depends entirely on how hard you press it in — 220 g packed against 175 g spooned loosely. Where a sugar isn't pure sucrose (icing sugar carries about 3% cornflour, brown sugar about 2% moisture in its molasses) the calculator discounts that before working out the honey, and nets the sugar's own moisture off the liquid reduction.
A few things this doesn't calculate: