Oven Temperature Converter

How this oven conversion is calculated

Fahrenheit and Celsius use the ordinary formulas. From Fahrenheit, Celsius = (F − 32) × 5 ÷ 9. From Celsius, Fahrenheit = C × 9 ÷ 5 + 32. Gas Mark does not use that formula. The page looks up a fixed table, in degrees Celsius: 0.25 → 110, 0.5 → 120, 1 → 140, 2 → 150, 3 → 160, 4 → 180, 5 → 190, 6 → 200, 7 → 220, 8 → 230, 9 → 240, 10 → 260. A gas mark between two of those keys is a straight line between the two Celsius numbers. Gas mark 4.5 sits halfway between 180 and 190, so it becomes 185°C. A gas mark at or below 0.25 stays at 110°C. A gas mark at or above 10 stays at 260°C. The page does not extrapolate past the ends of the table.

Going back to a gas mark is a different step. The page picks the table key whose Celsius value is closest to the Celsius it already has. It does not reverse the interpolation. If two keys are equally far, the earlier one in the list is kept, and the integer marks are checked before 0.25 and 0.5. The result line shows one decimal for Fahrenheit and Celsius. The summary line rounds Fahrenheit and Celsius to whole degrees, then appends the closest gas mark. Those two roundings are why one recipe temperature can show 176.7°C in the result and 177°C in the summary.

A short label is chosen from the Celsius value, using these cuts and no others: under 120, "Very low / warm"; under 150, "Low (slow oven)"; under 180, "Moderate-low"; under 200, "Moderate (350-400F range)"; under 220, "Moderate-hot"; under 240, "Hot"; otherwise "Very hot." The words inside the moderate label are text in the code. They are not a second conversion. 350°F is 176.7°C, which is under 180, so the label is "Moderate-low," even though the next label mentions 350.

Worked examples

Example 1: 350°F, the usual bake, and why 180°C is a different path

Enter 350, from Fahrenheit, to Celsius. Celsius = (350 − 32) × 5 ÷ 9 = 176.666…, and the result line shows 176.7°C. The summary line shows 350°F = 177°C = Gas mark 4, because 176.7 rounds to 177 at zero decimal places and 176.7 is closer to the table's 180 (gas 4) than to 160 (gas 3). The label is "Moderate-low." If you instead type gas mark 4 as the input, the table returns 180°C exactly, and the Fahrenheit line is 180 × 9 ÷ 5 + 32 = 356°F. The summary is 356°F = 180°C = Gas mark 4. Both are what this page does. They are not the same number. A chart that prints "350°F / 180°C / Gas 4" is pairing the gas-mark table with a rounded Fahrenheit, not the exact Fahrenheit-to-Celsius result.

Example 2: 220°C and gas mark 7

Enter 220, from Celsius, to Fahrenheit. Fahrenheit = 220 × 9 ÷ 5 + 32 = 428, so the result is 428°F. The summary is 428°F = 220°C = Gas mark 7, because the table's gas 7 is 220°C exactly. The label is "Hot," since 220 is not under 220. Entering gas mark 7 as the input produces the same 220°C and 428°F. It does not produce 425°F. If a recipe says 425°F, convert 425: Celsius = (425 − 32) × 5 ÷ 9 = 218.333…, the result line shows 218.3°C, and the summary shows 425°F = 218°C = Gas mark 7.

Example 3: A gas mark between two keys

Enter 4.5 as a gas mark. The page interpolates: halfway from 180 to 190 is 185°C. Fahrenheit = 185 × 9 ÷ 5 + 32 = 365°F. The result, if you convert to Celsius, is 185°C. The summary still says Gas mark 4, not 4.5, because 185 is 5 degrees from gas 4's 180 and 5 degrees from gas 5's 190, and the tie keeps the earlier key, which is 4. The label is the moderate one, because 185 is under 200 and not under 180. Gas mark 1 is the table value 140°C, which is 284°F, labeled "Low (slow oven)."

When to use this

Use it when the recipe and the oven dial are in different systems: a Fahrenheit recipe on a Celsius oven, a Celsius recipe on a Fahrenheit oven, or a British gas-mark recipe on either. It is not a timer, and it does not change bake time when you change pans. Pan area is the Cake Pan Size Converter. Common pairs from that area math are on the baking pan conversion chart. Cups and grams are the Cooking Measurement Converter. Kelvin, a fever, or a weather report belongs on the Temperature Converter, which has no gas mark and rounds differently: 350°F there displays as 176.6667°C, and its three-scale line shows 176.67°C rather than this page's whole-degree 177.

What the page does not adjust

Fan, convection, air-fry, dark pans, and glass pans are not in the formula. If the recipe already prints a lower fan temperature, enter that number. Do not convert the conventional temperature and then assume this page subtracted something. It didn't. An oven thermometer measures the cavity you have. This page only renames the setpoint. Altitude is not in the formula either. Internal food temperature is a probe reading, not the dial. The label "Hot" is a band on the Celsius number, not a doneness test.

The gas table is the list above, not a manufacturer's dial. If your cooker manual prints a different Celsius beside gas mark 4, the manual is the appliance and this table is the page. Enter the manual's Celsius directly when you need that appliance rather than the table.

Common mistakes

• Treating 180°C as the Fahrenheit conversion of 350°F. The Fahrenheit formula on this page produces 176.7°C. 180°C is the gas mark 4 table entry, and it converts back to 356°F.
• Reading only the summary line. The summary rounds to whole degrees. The result line keeps one decimal. 350°F is 176.7 on one line and 177 on the other.
• Expecting gas mark 4.5 to come back as 4.5. Interpolation runs when gas is the input. The summary always snaps to the nearest table mark, and an exact tie stays with the earlier mark.
• Subtracting a convection offset twice. The page applies no offset. If you already chose the recipe's fan number, convert that number alone.
• Using the moderate label as a temperature. The parenthetical "350-400F range" is a phrase on the under-200°C band. 350°F itself falls in "Moderate-low" because 176.7 is under 180.
• Asking this page for Kelvin. It has Fahrenheit, Celsius, and gas mark. Kelvin is the measurement temperature tool.

Limitations

Three input systems, one fixed gas table, linear interpolation only between listed gas marks, closest-mark snap on the way back, and labels at the Celsius cuts listed above. No rack position, no humidity, no pan color, no altitude, and no cook time. Rounding on the result is one decimal place for degrees. Rounding on the summary is a whole degree. Gas marks below 0.25 and above 10 are clamped to the end of the table rather than rejected.

FAQ

Why does 350°F become 176.7°C here and 180°C on a chart?

176.7°C is (350 − 32) × 5 ÷ 9, shown to one decimal. 180°C is the Celsius value stored for gas mark 4. Entering 350°F shows gas mark 4 on the summary because 176.7 is closest to that table row. Entering gas mark 4 shows 180°C and 356°F.

Why do the result and the summary disagree by a degree?

The result keeps one decimal. The summary rounds Fahrenheit and Celsius to whole degrees. 176.7°C rounds to 177°C on the summary. Both lines use the same unrounded Celsius before that rounding.

What does gas mark 4.5 convert to?

185°C and 365°F. The summary's gas mark snaps back to 4, because 185 is equally far from the 180°C and 190°C rows and the tie keeps gas mark 4.

Does this lower the temperature for a fan oven?

No. Convert the number you intend to set. If the recipe already gives a fan temperature, use that number as the input. The page will not subtract a second offset.

Why is 350°F labeled moderate-low when the next label mentions 350?

Labels use Celsius cuts. 350°F is 176.7°C, and the moderate-low band runs up to but not including 180°C. The words "350-400F range" are part of the label for the band from 180°C up to 200°C. They are not applied to 350°F.

Can I convert a gas mark my dial does not list, such as 11?

Anything at or above 10 is clamped to 260°C, which is 500°F and gas mark 10 on the way back. Anything at or below 0.25 is clamped to 110°C. The page does not extend the table.

Which page should I use for a fever or for Kelvin?

The measurement Temperature Converter. It converts Fahrenheit, Celsius, and kelvin, and it does not have gas marks. This page is the oven table plus the degree formulas.

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