Translate °F, °C and Gas Mark — exact values plus the rounded settings real ovens want.
A British recipe says Gas Mark 4. Your American oven says 350°F. Your German friend’s recipe says 180°C. All three mean the same oven. Our free Oven Temperature Converter translates between Fahrenheit, Celsius, and Gas Mark — showing both the exact conversion and the oven-friendly rounded values you should actually dial in.
Oven temperature is the single most mistranslated number in cooking. Fahrenheit and Celsius are related by a clean linear formula, but Gas Mark — the British system — is a discrete scale (whole numbers 1 to 9) invented for gas ovens, where each mark is roughly a 25°F step. There is no formula for Gas Mark: it’s a lookup table, and converting means finding the nearest mark. That discreteness is the whole point: ovens are imprecise instruments, and Gas Mark is honest about it.
Enter a temperature in any scale and the widget shows all three — plus the rounded values real ovens want.
Fahrenheit (°F) is the American kitchen scale: water freezes at 32°F, boils at 212°F, and most baking happens between 325°F and 450°F. Celsius (°C) is the rest of the world’s: 0°C freezing, 100°C boiling, baking at 160–230°C. The conversion is linear: C = (F − 32) × 5/9 and F = C × 9/5 + 32. Clean, exact, reversible.
Gas Mark is different in kind. It runs 1–9 (sometimes ¼, ½, 1, 2… at the low end), and each step is about 25°F / 14°C. The standard table: GM 1 = 140°C/275°F, GM 2 = 150°C/300°F, GM 3 = 170°C/325°F, GM 4 = 180°C/350°F, GM 5 = 190°C/375°F, GM 6 = 200°C/400°F, GM 7 = 220°C/425°F, GM 8 = 230°C/450°F, GM 9 = 240°C/475°F. Notice the uneven steps — 3→4 jumps 20°F in the table while 6→7 jumps 25°F. That unevenness is why Gas Mark is a nearest-match conversion, not a formula: the widget finds the mark whose Celsius value is closest to your temperature.
The deeper truth: your oven lies by ±25°F. Home ovens cycle above and below the set point, thermostats drift, and hot spots vary by shelf. Converting 350°F to 176.67°C is mathematically honest and culinarily silly — set 180°C. The widget shows the exact value for correctness and the rounded-to-5 value for the dial. Trust the rounded one.
Key terms:
Round oven settings to the nearest 5 degrees — finer precision is below your oven’s accuracy.
An American cookie recipe says 375°F. Your UK oven shows Gas Mark.
375°F ↔ 190°C ↔ GM 5 is one of the cleanest triples on the table — no rounding angst.
A French tart recipe says 200°C. Your US oven needs Fahrenheit.
When the exact conversion lands between dial detents, pick the nearer one — 8°F is invisible to pastry.
An American in London roasts a turkey from a US recipe: 325°F. Convert: (325 − 32) × 5/9 = 162.8°C. Nearest mark: GM 3 = 170°C/325°F — exact on the Fahrenheit side. Her UK oven dial shows Gas Marks, so she sets GM 3. The turkey’s internal thermometer — the only temperature that truly matters — reads 165°F at the thigh when done. Oven conversion got her in the zone; the meat thermometer finished the job. This is the professional’s hierarchy: convert the oven setting, but trust the food’s internal temperature.
Second scenario: sourdough in Berlin. A US recipe says 450°F for the Dutch oven bake. Convert: (450 − 32) × 5/9 = 232.2°C → 230°C, GM 8. Her oven maxes at 250°C with a digital display, so she sets 230°C exactly. The loaf’s ear opens beautifully — because at bread temperatures, ±10°C changes crust color, and she was within 2°C.
Third: the slow braise. A recipe says Gas Mark 2 (150°C/300°F) for a 4-hour lamb shoulder. A friend’s Celsius-only oven: set 150°C. A Fahrenheit oven: 300°F. All three cooks’ shoulders fall off the bone at the same time — slow cooking is forgiving, and the discrete Gas Mark scale was designed for exactly this imprecision.
Fifth: the calibration bake. A cook suspects her oven runs hot: she converts 350°F → 175°C, bakes a test batch of shortbread at 175°C, and it browns in 12 minutes instead of 18. She drops to 160°C next time — effectively learning her oven’s personal offset (−15°C). Conversion gave the starting point; one empirical bake gave the correction. Professionals do this with every unfamiliar oven: convert, bake, adjust, and note the offset on the oven door with a magnet.
Fourth: broiler confusion. A recipe says “Gas Mark 9” for finishing gratins — that’s 240°C/475°F, the top of the scale. A US cook converts to 475°F and sets the oven to bake; the British cook might use the grill. Same number, different heat direction — conversion handles the number, but convection vs. radiant heat is a separate decision (see fan-oven notes below).
Recipe publishing: international cookbooks print all three scales; the converter is the tool food editors use to generate them without table errors.
Appliance manufacturing: ovens sold globally show °C or °F by market; the underlying thermostat is the same — only the dial printing changes.
Food safety: safe internal temperatures (165°F poultry = 74°C) are converted exactly the same way; the formula doesn’t care what’s being measured.
Industrial baking: tunnel ovens run in Celsius worldwide; American bakery formulas get converted once, then baked by the thousand.
Kilns and forges: the same F/C math scales up to ceramics (cone temperatures) and metallurgy — Gas Mark just stops at 9.
Weather: the same two formulas convert forecasts; an oven is just a very small, very hot climate.
One pattern worth internalizing: convert exactly, then round to the oven’s reality. Precision in the math, forgiveness in the dial.
Why Gas Mark exists: early gas ovens had numbered dials with no thermometers — Regulo burners (from the 1920s) let cooks say “Regulo 4” the way we’d say medium heat. The numbers stuck in Britain even after thermostats arrived, because a 9-step scale matches how ovens actually behave: coarse. The US kept Fahrenheit dials; metric countries went Celsius; Britain kept the marks. Three scales, one physics.
Edge cases and pro tips: below GM 1 (¼, ½ marks exist on some dials: ¼ = 110°C/225°F, ½ = 130°C/250°F) — the widget covers 1–9, the practical baking range. Above GM 9, you’re at pizza-oven territory (260°C+); convert with the formula. Fan ovens: subtract 20°C from any converted value, or equivalently treat GM 4 as a fan 160°C. And dark pans bake faster than the set temperature suggests — drop 25°F when switching from shiny aluminum to dark nonstick.
When conversion is the wrong tool: if your bakes keep failing at the “right” temperature, stop converting and buy an oven thermometer — the problem is calibration, not arithmetic. For candy and sugar work, the thermometer goes in the sugar, not the oven; oven conversion is irrelevant there. And for sous-vide, the circulator holds ±0.5°C — convert once, then trust the machine completely.
Oven Temperature Converter: F=(C*9/5)+32, C=(F-32)*5/9. Gas Mark is a nearest-match lookup: GM1=140C/275F, GM2=150C/300F, GM3=170C/325F, GM4=180C/350F, GM5=190C/375F, GM6=200C/400F, GM7=220C/425F, GM8=230C/450F, GM9=240C/475F. Round to nearest 5 degrees; fan ovens subtract 20C. Source: Sigma Calculator, Oven Temperature Converter, https://sigmacalculator.net/cooking-calculators/oven-temperature-converter/
Cite this page as: Oven Temperature Converter, Sigma Calculator, https://sigmacalculator.net/cooking-calculators/oven-temperature-converter/
Last updated: October 12, 2026