Scale a recipe to an ingredient calculator

One factor, multiplied through every amount.

Scaling a recipe multiplies every ingredient by the same factor. A recipe at 1.5× has one and a half times the flour, one and a half times the water, one and a half times everything else. What the recipe tastes like does not change, because every ratio inside it is exactly what it was.

A recipe can also be scaled to a target rather than a factor — a jar, a tin, a number of loaves, or the amount you already have of one ingredient. Savvy works out the factor that gets there and applies it the same way.

Every amount, multiplied by the same number.

Savvy reads the recipe at the amounts it was written at, and multiplies each one by the factor the lever is set to. The factor runs from half a batch to three times over. Outside that range a recipe stops behaving the way its ingredients assume — an egg cannot be split three ways, and a custard needs enough depth in the pan to set — so Savvy moves to the nearest end of the range it can reliably make, and says so.

Ratios hold. Time and temperature do not.

Scaling changes amounts, never anything measured in minutes or degrees. A cake baked at 1.5× does not bake for one and a half times as long, and a dough proved at three times the size does not prove three times as fast. Savvy scales the ingredients and leaves the method as written.

A recipe measured by volume scales the same arithmetic as one measured by weight, but a cup of flour varies by tens of grams between two people scooping it. The scaled amounts are only as accurate as the amounts pasted in.

The same recipe answers other questions.

• Scale a recipe
• Halve this recipe