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What is the Fahrenheit equivalent of UK gas mark?

By Paulo de VriesLast verified 2026-05-214 sources~3 min readhigh consensus

What we know

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.

3 variables shift this number4 cited sources3 common mistakes addressed~3 min read read below

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The full answer

The UK gas mark scale (every cookbook before 1990 in the UK)

UK 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.

Full conversion table

Gas Mark	Fahrenheit	Celsius	Use
1/4	225°F	110°C	Very low — meringues, drying, slow desiccation
1/2	250°F	120°C	Very low — fruit drying, slow-roast tomatoes
1	275°F	135°C	Low — slow-cook fruitcake, slow-bake meringues
2	300°F	150°C	Low — slow braising, custards, dehydrating
3	325°F	165°C	Moderate-low — long bakes, banana bread, casseroles
4	350°F	180°C	Moderate — most cookies, sponges, layer cakes
5	375°F	190°C	Moderate-high — banana bread, muffins, brownies
6	400°F	200°C	Hot — roasting vegetables, pies, quick breads
7	425°F	220°C	Hot — pizza, bread, hot roasting
8	450°F	230°C	Very hot — pizza, artisan bread, broiling-adjacent
9	475°F	245°C	Very hot — pizza on stone, intense bread crust

Formula

> Fahrenheit = (gas mark × 25) + 250

Examples: - Gas Mark 4 → 4 × 25 + 250 = 100 + 250 = 350°F ✓ - Gas Mark 7 → 7 × 25 + 250 = 175 + 250 = 425°F ✓ - Gas Mark 9 → 9 × 25 + 250 = 225 + 250 = 475°F ✓

Half marks: GM 4.5 → 362.5°F (round to 360 or 365 — depends on recipe). GM 6.5 → 412°F (round to 410-415).

Why the scale exists

Before 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.

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.

Time ranges by condition

Condition	Duration	Note
UK gas-mark recipe	5 seconds	°F = (GM × 25) + 250
Half gas mark	5 seconds	(0.5 × 25) = +12.5°F per half mark
Older UK recipes (gas mark only)	10 seconds	Common in pre-1990s UK cookbooks

What changes the time

Oven calibration. Even modern UK ovens may run 5-15°F off the dial. Use an oven thermometer if precision needed.
Gas-mark steps. Each step = 25°F. Half marks = 12.5°F. Quarter mark (rare) = 6.25°F.
Conversion direction. GM → F: × 25 + 250. F → GM: (F - 250) / 25.

Common questions

Why don't most American cookbooks use gas mark?

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.

My UK recipe says "Gas Mark 4 / 350°F" — should I use 350 or convert?

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.

Does Gas Mark 4 = 350°F for both regular bake and convection?

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).

Sources

We cite primary research, expert practice, and authoritative reference. Higher-tier sources weighted heavier. See methodology.

Tier 1 · peer-reviewed / governmentalTier 2 · editorial referenceTier 3 · named practitioner

T2Mary Berry, "Baking Bible" — Authoritative UK baking reference; gas mark + temperature conversions throughout
T2BBC Good Food — Oven Conversion Guide — Authoritative UK baking publication conversion guide
T1NIST — Temperature scale conversions — Government metric/imperial standards
T2Delia Smith, "How to Cook" series — Definitive UK reference includes gas-mark equivalency tables

Books referenced in this answer

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Baking Bible — Mary BerryFind on Amazon

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What could change this answer

honest uncertainty

We don’t know your specific equipment, ingredient batch, or environment. This answer is the best directional estimate from cited sources. Here’s where it’s less certain:

3 factors shift the answer. Your specific oven calibration, gas-mark steps, conversion direction can move this estimate in either direction. The table below shows the documented ranges.
Range spans 3 documented conditions. Pick the row that matches your scenario; halfway between two rows is your best estimate. The widest condition you can imagine is the safer upper bound.
Treat as a directional starting point. Real-world equipment, ingredient batch, and ambient conditions cause natural variance the table cannot capture. Use sensory checks (sight, smell, touch, internal temperature when relevant) alongside this answer — not instead of it.
Backed by 4 cited sources — verify if precision matters. See the Sources section for primary references. Cross-check the cited materials when stakes are high: commercial production, food safety, allergens, dietary or medical considerations.
Verified 100 days ago. If you found a better-sourced answer or our answer no longer matches reality, tell us — corrections are public and dated. The page exists to be accurate, not to be unchanged.

Cite this page

de Vries, P. (2026). What is the Fahrenheit equivalent of UK gas mark?. AskedWell. Retrieved 2026-08-29, from https://askedwell.com/pages/how-to-convert/gas-mark-to-fahrenheit

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Last verified: 2026-05-21 · Published 2026-05-21

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