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Oven temperature and pan size converter

Convert oven temperatures between °C, °F, fan oven and gas mark, and work out how much to scale a recipe for a different round, square or rectangular pan.

Updated Checked against 9 worked examples

Try
Conventional oven
°C
Conventional oven: 176.7 °C
Shown to up to 1 decimal places, half-up
Conventional oven
350°F
Fan oven
156.7°C
Gas mark
4
Fan ovens vary; Which? puts the usual reduction at about 20 °C, and your oven's manual gives the figure for that model.

350 °F is 177 °C in a conventional oven, 157 °C in a fan oven, and gas mark 4.

Oven heat (°C, conventional)

Very coolCoolModerateHotVery hot90130185210235290Fan setting177 °C
How it's calculated S
  1. Fahrenheit to Celsius

    (350−32)×59=176.67 ∘C(350 - 32) \times \tfrac{5}{9} = 176.67\,^\circ\text{C}
  2. Fan oven

    176.67−20=156.67 ∘C176.67 - 20 = 156.67\,^\circ\text{C}
  3. Nearest gas mark

    350 °F is closest to gas mark 4 (350 °F).

About the oven temperature and pan size converter

Oven temperatures convert with °F = °C × 9/5 + 32. A fan oven is set about 20 °C below a conventional one, and gas mark 1 is 275 °F (140 °C), with each mark adding 25 °F. For pans, the ingredient factor is the area of your pan divided by the area of the recipe's pan, which keeps the batter at the same depth.

The default converts 350 °F: 176.7 °C, which recipes round to 180 °C, or 156.7 °C in a fan oven (usually written 160 °C), and gas mark 4. In pan mode, a 9-inch round pan (63.6 sq in) and an 8-inch square pan (64 sq in) hold almost the same amount, a factor of 1.006.

Oven thermostats and fans vary, so treat the converted setting as a starting point. When batter ends up deeper or shallower than the recipe intended, check for doneness early.

Worked examples

350 °F to °C

Convert
Oven temperature
Oven setting
350
Setting is in
°F
Convert to
°C
Conventional oven
176.7 °C
Fan oven
156.7 °C
Gas mark
4

Checked against: Python decimal: (350 − 32) × 5/9; gas mark 4 = 350 °F (gas mark table)

180 °C to °F

Convert
Oven temperature
Oven setting
180
Setting is in
°C
Convert to
°F
Conventional oven
356 °F
Gas mark
4

Checked against: 180 × 9/5 + 32 = 356; nearest mark is 4 (350 °F)

Gas mark 1/4

Convert
Oven temperature
Oven setting
1/4
Setting is in
Gas mark
Convert to
°C
Conventional oven
107.2 °C
Conventional oven
225 °F

Checked against: Gas mark table: 1/4 = 225 °F; Python decimal (225 − 32) × 5/9

Fan 160 °C to °F

Convert
Oven temperature
Oven setting
160
Setting is in
Fan °C
Convert to
°F
Conventional oven
356 °F
Conventional oven
180 °C

Checked against: Which? rule: fan + 20 = 180 °C conventional; 180 × 9/5 + 32

Questions

What is 180 °C in Fahrenheit?

356 °F, from 180 × 9/5 + 32. Recipes round it to 350 °F, which is gas mark 4, and the Which? oven conversion table puts 180 °C, 160 °C fan, 350 °F and gas mark 4 on the same row. Going the other way, 350 °F is exactly 176.7 °C.

How much lower should a fan oven be?

About 20 °C lower than the conventional temperature, according to Which?, so 180 °C becomes 160 °C fan and 200 °C becomes 180 °C fan. The fan moves hot air over the food, and leaving the setting unchanged can cook the outside too quickly. Oven makers' manuals give the figure for a specific model.

What temperature is gas mark 4?

180 °C (350 °F), or 160 °C in a fan oven. Gas mark 1 is 140 °C (275 °F) and each mark adds 25 °F, about 14 °C: gas 6 is 200 °C (400 °F) and gas 9 is 240 °C (475 °F), as listed in the Which? table. The Celsius values are rounded to the nearest 10 °C.

Can I use an 8-inch square pan instead of a 9-inch round one?

Yes. A 9-inch round pan has an area of π × 4.5² = 63.6 square inches and an 8-inch square pan has 64, so the recipe needs no change. A 9 × 13 inch pan has 117 square inches, 1.84 times the 9-inch round, so batter for the rectangle fills nearly two round pans to the same depth.

How do you adjust a recipe for a different cake tin?

Multiply every ingredient by the new tin's area divided by the old tin's area. For round tins that is the ratio of the diameters squared: moving from a 20 cm to a 23 cm tin is (23 ÷ 20)² = 1.32, so use about a third more of everything. The batter then sits at the same depth, so the baking time stays close to the original.

How accurate is the oven temperature and pan size converter?

Accuracy depends on your inputs and the method's assumptions. Decimal arithmetic uses 50 significant digits, but estimates, numerical methods and source data can be less precise; the displayed rounding does not remove those limits. It is checked against 9 worked examples whose answers come from independent sources; for example, “350 °F to °C” is checked against Python decimal: (350 − 32) × 5/9; gas mark 4 = 350 °F (gas mark table).

Where does the method come from?

Gas mark — conversion table (1 = 275 °F, +25 °F per mark); Which? — Oven temperature conversion table (fan ovens 20 °C lower).

About this calculator

∘F=∘C×95+32fan=∘C−20pan factor=Ayour panArecipe pan\begin{gathered}{}^\circ F = {}^\circ C \times \tfrac{9}{5} + 32 \\ \text{fan} = {}^\circ C - 20 \\ \text{pan factor} = \frac{A_{\text{your pan}}}{A_{\text{recipe pan}}}\end{gathered}

Sources

  1. Gas mark — conversion table (1 = 275 °F, +25 °F per mark)
  2. Which? — Oven temperature conversion table (fan ovens 20 °C lower)

Checked against references

9 worked examples with independently sourced answers ship with this calculator. They run in the test suite; you can run them here too.

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