Published August 1, 2026

Common Recipe Substitutions and Their Measurements

Every home cook eventually hits the moment mid-recipe when they realize they're out of buttermilk, brown sugar, or cake flour. The good news is that most common baking ingredients have reliable substitutes — but getting the measurements right matters, since a substitution with the wrong ratio can throw off both the recipe's chemistry and its final weight or volume.

Buttermilk substitute

For each cup of buttermilk, stir 1 tablespoon of white vinegar or lemon juice into 1 cup of regular milk, then let it sit for 5-10 minutes until slightly thickened. This is a 1:1 volume substitution — you don't need to adjust the amount, since the acid is what matters for the recipe's chemistry (reacting with baking soda), not the substitute's exact density.

Brown sugar substitute

If you're out of brown sugar, combine 1 cup of granulated sugar with 1 tablespoon of molasses (2 tablespoons for dark brown sugar) and mix thoroughly. This is also roughly a 1:1 cup-for-cup substitution by volume, though keep in mind that packed brown sugar (213 g/cup) is denser than granulated sugar (200 g/cup) — if a recipe specifies weight rather than volume, use the closer 213g target and add a touch more molasses if the texture needs it.

Cake flour substitute

For each cup of cake flour, use 1 cup of all-purpose flour minus 2 tablespoons, replaced with 2 tablespoons of cornstarch. Since all-purpose flour and cornstarch have similar densities, this substitution holds up reasonably well by both volume and weight — expect a final weight close to the standard 120 grams per cup of all-purpose flour, slightly adjusted by the cornstarch swap.

Sour cream / Greek yogurt

Plain Greek yogurt substitutes for sour cream at a 1:1 ratio by volume in most recipes, and the two have similar enough density that weight-based recipes convert cleanly too. Full-fat yogurt works best for baking; low-fat versions can make baked goods slightly drier.

Honey and sugar

Substituting honey for granulated sugar (or vice versa) is trickier because their densities are very different — honey weighs about 340 grams per cup versus sugar's 200 grams per cup — and honey adds liquid volume the recipe wasn't accounting for. As a general rule, replace 1 cup of sugar with 3/4 cup of honey, and reduce another liquid in the recipe by about 3 tablespoons per cup of honey used, plus reduce oven temperature by 25°F to prevent over-browning from honey's natural sugars.

Table: quick substitution ratios

Why measurement units matter more with substitutions

Substitutions are exactly the moments when converting carefully matters most, since you're already introducing one variable (a different ingredient) into the recipe. Keeping your volume-to-weight conversion accurate for whichever ingredient you're actually using — rather than assuming every cup weighs the same — helps prevent a substitution from compounding into a bigger error. Use our measurement converter to double check cup, gram, and ounce equivalents whenever you're swapping ingredients, and see our guide on why ingredient density affects cup weight for more on why this matters.

The takeaway

Most common substitutions work well at a simple 1:1 volume ratio, but a few — especially honey for sugar — require both a ratio adjustment and a recipe tweak elsewhere (liquid or oven temperature). When in doubt, convert to weight for the ingredient you're actually using rather than assuming the substitute behaves identically to the original.