Gas marks, fan ovens and “my tin is 8-inch” — the math, solved
OvenMath converts oven temperatures between °C, °F, gas marks and fan settings, and works out what your pan holds — with the methodology and the sources shown, not hidden. Every tool runs in your browser and nothing is sent anywhere.
The two tools bakers bookmark
Client-side, offline-capable, and each one explains exactly where its numbers come from.
Reference charts
The pillars: every row verified against published sources on 2026-11-16.
Guides
The questions that send bakers to the search box, answered with sources.
Fan vs conventional ovens: the 20°C rule
Where “reduce by 20°C” comes from, when it's 15 or 25, and why fan ovens bake faster.
OvensThe gas mark system explained
Gas marks are a Fahrenheit scale in disguise — 275 + 25 per step. Here's the whole system.
OvensWhy “preheat properly” + oven thermometers
Real ovens swing and drift; Delia's team recommends a thermometer and so do we. Here's why.
OvensCommon baking temperature mistakes
Too-hot cakes, pale bottoms, twice-converted fan temps — the seven mistakes we see most.
PansPan substitution math explained
Area, volume and batter depth — how to swap any tin for any other without a soggy centre.
PansSilicone vs metal pans
Silicone insulates, metal conducts: what each does to temperature, time and browning.
ScienceBaking at altitude: the basics
Colorado State Extension's elevation tables, translated: temperature, leavening, liquid, sugar.