Baking is the one kind of cooking where the numbers are supposed to be exact, and almost none of them are. A cup is a volume pretending to be a weight, and the two charts that matter most disagree about the conversion: King Arthur Baking puts a cup of all-purpose flour at 120 g and the USDA puts it at 125 g, which is mild, while bread flour is 120 g against 137 g, which is not. A gas mark is a detent on a dial rather than a temperature, and Which? and Smeg file gas mark 4 under the same 180 °C but different Fahrenheit — 350 against 356 — because one is quoting American oven numbers and the other is converting its own column. Even the pan is not what it says: a 9 inch round holds a quarter more than an 8 inch one, and an 8 inch square holds the same as the 9 inch round to within one percent. Only the geometry and the Celsius to Fahrenheit line are beyond argument, and these tools mark which is which — the exact arithmetic done exactly, every borrowed figure carrying the name of whoever published it, and disagreements printed next to each other instead of split down the middle.
Tools in this category
Cups to grams converter
Turn cups of a baking ingredient into grams against two published charts at once, kept apart with the source beside each number rather than averaged.
Baking pan conversion calculator
Scale a recipe from the pan it was written for to the pan you own, and see what the swap does to batter depth and bake time, which do not scale with it.
Oven temperature conversion
Celsius, Fahrenheit, gas mark and fan, read off the published chart you pick — because gas marks and fan offsets are conventions and the charts disagree.
Suggest a tool
Tell us what is missing and where its numbers should come from.
What should it convert, calculate or generate, and where would the authoritative numbers come from? A link to the standard or publication that defines them is the most useful thing you can send.
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How these tools are built
Every tool in this category runs entirely in your browser: there is no upload, no account and no request to a server once the page has loaded. The numbers behind them are transcribed from the organisation that defines them — NIST for units, the W3C for web formats, the WHO for health measures — and each page names its source next to the formula. A tool whose reference values stop reproducing fails the build and does not ship, which is the whole reason the catalogue grows slowly.