Guides to the arithmetic of cooking

Each calculator on this site states its method on its own page. These are the longer arguments behind those methods — where the numbers come from, how big the errors are, and when the standard advice stops being true for your kitchen.

Why weighing beats measuring cups A cup of flour is anywhere from 113 to 150 grams depending on how it got into the cup. The size of that error, where it comes from, and why it lands hardest on exactly the bakes people find hardest. Guide
Bake times when you change pan size Bake time follows the depth of the batter, not the width of the tin — which is why a wider pan bakes faster, not slower, and why deep cakes are the ones that come out raw in the middle. Guide
Baking at altitude Above about 3,000 feet water boils cooler, gases expand harder and everything dries out faster. The four adjustments that matter, in the order to make them. Guide
How much cake does a tin actually serve The same 9-inch round is eight servings at home and sixteen at a wedding. How portion conventions work, and how to size a tin for the room you are actually feeding. Guide
Why dough temperature beats clock time The single variable that decides whether a recipe’s timings apply in your kitchen, and what to do about it without buying anything. Guide
How much food per person, actually Where the standard catering numbers come from, why they overshoot when you serve three dishes, and the items hosts consistently get wrong. Guide

Where to start

If a bake keeps coming out differently each time you make it, read why weighing beats measuring cups first. It is the largest single source of variation in home baking and the cheapest one to remove.

If you are standing in front of the wrong tin right now, the pan size converter answers it in a few seconds and bake times when you change pan size explains what it did.

If you live somewhere high and nothing has behaved since you moved, baking at altitude is the one to read, and it is worth reading before you blame your oven.

The tools these guides belong to

Every guide links to the calculator it supports, and every calculator links back. Nothing here is gated, nothing asks for an email address, and there are no affiliate links to equipment.