{"schema":"askedwell-answer-v1","url":"https://askedwell.com/pages/how-to-convert/gas-mark-to-fahrenheit","question":"What is the Fahrenheit equivalent of UK gas mark?","short_answer":"Gas Mark 4 = 350°F (180°C). Each gas-mark step = 25°F. Gas Mark 1 = 275°F, GM 3 = 325°F, GM 5 = 375°F, GM 7 = 425°F, GM 9 = 475°F. Formula: °F = (gas mark × 25) + 250.","long_answer":"**The UK gas mark scale (every cookbook before 1990 in the UK)**\n\nUK gas-mark ovens use an integer scale 1/4 to 9 (rather than degrees). The Gas Mark scale dates from the 1930s when British home ovens were calibrated in gas-flow increments rather than thermometer readings. Each step = 25°F (about 14°C) of oven temperature.\n\n**Full conversion table**\n\n| Gas Mark | Fahrenheit | Celsius | Use |\n|---|---|---|---|\n| 1/4 | 225°F | 110°C | Very low — meringues, drying, slow desiccation |\n| 1/2 | 250°F | 120°C | Very low — fruit drying, slow-roast tomatoes |\n| 1 | 275°F | 135°C | Low — slow-cook fruitcake, slow-bake meringues |\n| 2 | 300°F | 150°C | Low — slow braising, custards, dehydrating |\n| 3 | 325°F | 165°C | Moderate-low — long bakes, banana bread, casseroles |\n| 4 | 350°F | 180°C | Moderate — most cookies, sponges, layer cakes |\n| 5 | 375°F | 190°C | Moderate-high — banana bread, muffins, brownies |\n| 6 | 400°F | 200°C | Hot — roasting vegetables, pies, quick breads |\n| 7 | 425°F | 220°C | Hot — pizza, bread, hot roasting |\n| 8 | 450°F | 230°C | Very hot — pizza, artisan bread, broiling-adjacent |\n| 9 | 475°F | 245°C | Very hot — pizza on stone, intense bread crust |\n\n**Formula**\n\n> Fahrenheit = (gas mark × 25) + 250\n\nExamples:\n- Gas Mark 4 → 4 × 25 + 250 = 100 + 250 = 350°F ✓\n- Gas Mark 7 → 7 × 25 + 250 = 175 + 250 = 425°F ✓\n- Gas Mark 9 → 9 × 25 + 250 = 225 + 250 = 475°F ✓\n\nHalf marks: GM 4.5 → 362.5°F (round to 360 or 365 — depends on recipe). GM 6.5 → 412°F (round to 410-415).\n\n**Why the scale exists**\n\nBefore electric ovens with thermostats (~1960s onward), British gas ovens used a regulator dial labeled 1-9 (or 1-10 in some older models). The gas-flow rate corresponded to consistent oven temperatures. The numbers stuck even after thermostatic control became standard. Most UK recipes from the 1950s-1990s use Gas Mark; recipes from 2000+ usually list both °C and °F alongside the Gas Mark for convenience.\n\n**Cross-reference:** see /pages/how-to-convert/fahrenheit-to-celsius for direct F/C conversion + /pages/how-to-convert/celsius-to-fahrenheit for inverse + /pages/what-temperature-for/baking-bread for bread-specific temperatures.","ranges":[{"condition":"UK gas-mark recipe","duration":"5 seconds","note":"°F = (GM × 25) + 250"},{"condition":"Half gas mark","duration":"5 seconds","note":"(0.5 × 25) = +12.5°F per half mark"},{"condition":"Older UK recipes (gas mark only)","duration":"10 seconds","note":"Common in pre-1990s UK cookbooks"}],"variables":[{"name":"Oven calibration","effect":"Even modern UK ovens may run 5-15°F off the dial. Use an oven thermometer if precision needed."},{"name":"Gas-mark steps","effect":"Each step = 25°F. Half marks = 12.5°F. Quarter mark (rare) = 6.25°F."},{"name":"Conversion direction","effect":"GM → F: × 25 + 250. F → GM: (F - 250) / 25."}],"sources":[{"label":"Mary Berry, \"Baking Bible\"","note":"Authoritative UK baking reference; gas mark + temperature conversions throughout","tier":2},{"label":"BBC Good Food — Oven Conversion Guide","url":"https://www.bbcgoodfood.com/howto/guide/oven-conversion-table","note":"Authoritative UK baking publication conversion guide","tier":2},{"label":"NIST — Temperature scale conversions","url":"https://www.nist.gov/pml/owm","note":"Government metric/imperial standards","tier":1},{"label":"Delia Smith, \"How to Cook\" series","note":"Definitive UK reference includes gas-mark equivalency tables","tier":2}],"faq":[{"question":"Why don't most American cookbooks use gas mark?","answer":"American ovens (gas and electric) historically used Fahrenheit thermostatic control; the gas-mark numbered scale was specific to British (and some Commonwealth) gas ovens. The US adopted thermometer-based control earlier, so the numbered-dial system never caught on. When you encounter a UK recipe with gas marks, just convert using the formula or table above."},{"question":"My UK recipe says \"Gas Mark 4 / 350°F\" — should I use 350 or convert?","answer":"Use 350°F directly. Modern UK recipes typically print both gas mark and equivalent Fahrenheit/Celsius. The numbers are calibrated to be equivalent. The dual labeling exists for: (1) cooks with older gas ovens still using gas-mark dials, and (2) cooks with modern thermometer-controlled ovens reading the °F or °C value."},{"question":"Does Gas Mark 4 = 350°F for both regular bake and convection?","answer":"No — convection (fan-forced) ovens cook 20-25°F (10-15°C) lower than conventional. For Gas Mark 4 in a convection setting, use 325-330°F (165°C) instead of 350°F. Most modern UK recipes specify \"conventional\" temperature; if you have only a fan oven, reduce by one gas-mark step (or 25°F)."}],"keywords":["gas mark to fahrenheit","gas mark conversion","UK oven temperature","gas mark celsius","UK gas mark chart"],"category":"baking","date_published":"2026-05-21","date_modified":"2026-05-21","license":"CC-BY-4.0","attribution":"https://askedwell.com"}