170 C to F: 338°F Oven Conversion Chart + Fan Guide

Few baking disasters frustrate home cooks more than discovering their oven runs hot or cold — and the culprit is often a simple temperature mismatch. Whether you’re following a US recipe that calls for 338°F or adjusting your UK-built fan oven for continental instructions, nailing the right setting matters.

170°C to °F: 338°F · Fan oven equivalent: 150-160°C · Gas mark: 3 · Conventional oven: 325-350°F · Formula: °F = (°C × 9/5) + 32

What is 170 degrees Celsius in Fahrenheit?

The exact conversion follows a simple formula: multiply the Celsius value by 9/5, then add 32. Working through 170°C step by step: 170 × 1.8 = 306, and 306 + 32 = 338°F (Smeg UK appliance guide). You may encounter 325°F in some recipe charts, which is a rounded approximation that kitchen appliances tolerate well.

Conversion formula

The Celsius-to-Fahrenheit formula is °F = (°C × 9/5) + 32. For the reverse conversion — Fahrenheit to Celsius — subtract 32 from the Fahrenheit value, then multiply by 5/9 (Smeg UK). Memorising this makes every recipe adjustment automatic, whether you’re converting 180°C or 200°C.

Exact calculation

Using the formula gives 338°F as the mathematically precise result for 170°C. Many UK and US recipe sites round this down to 325°F for practical oven settings, a difference that rarely affects baking results but matters when precision is critical, such as when tempering chocolate or proofing yeast (Flawless Food baking blog).

What is 170 C for an oven?

A conventional oven set to 170°C is considered moderately hot — ideal for baked goods that need gentle, even heat such as cakes, brownies, and custards (Domestic & General appliance guide). This temperature sits in the lower-mid range of most domestic ovens, making it a versatile setting for both sweet and savoury recipes.

Conventional vs fan oven

The key difference lies in air circulation: fan ovens move hot air continuously, which means food cooks faster and at a lower temperature to achieve the same result. Reducing the setting by 20°C compensates for this accelerated cooking effect (Which.co.uk consumer review). Without this adjustment, your baked goods may brown too quickly on the outside while remaining underdone inside.

Baking applications

Recipes typically calling for 170°C conventional include sponge cakes (20-25 minutes), macarons for drying stages, and slow-roasted meats starting at higher temperatures before finishing lower. The 325-350°F range (rounded Fahrenheit equivalents) covers most US recipes that align with this Celsius setting.

What’s 170 C in a fan oven?

The standard adjustment when moving from a conventional to a fan oven is to reduce the temperature by 20°C. This means 170°C conventional translates to approximately 150°C in a fan oven (Flawless Food). Some newer fan ovens run slightly hotter or cooler, so the actual sweet spot may fall between 150°C and 155°C.

Fan oven reduction

Fan ovens circulate hot air throughout the cavity, transferring heat to food more efficiently than static heat. This accelerated transfer means recipes that work at 170°C in a conventional oven will finish faster — or burn — at the same temperature in a fan model (Domestic & General). The 20°C reduction accounts for this difference.

Adjusted temperature

When using an air fryer, apply a similar 15-20°C reduction since these appliances operate like compact fan ovens. For 170°C conventional, set your air fryer to 150-155°C and check food 5-10 minutes earlier than the recipe suggests. The more contained space and faster air circulation in air fryers can intensify cooking beyond standard fan oven behaviour.

What gas mark is 170 degrees in a fan oven?

Gas Mark 3 is the UK standard equivalent for 170°C conventional oven settings (Flawless Food). The Gas Mark scale ranges from 1 (cool) to 9 (very hot), with Gas Mark 3 falling in the moderately warm zone alongside 325°F or 160°C in conventional terms.

Gas mark chart

The Gas Mark system was developed for older British gas ovens and persists as a familiar reference for UK home cooks. Gas Mark 3 specifically corresponds to approximately 325°F / 160°C conventional / 140°C fan, making it slightly cooler than 170°C conventional — the precise match is often approximated as Gas Mark 3 in conversion tables (Which.co.uk).

Fan vs conventional

When a recipe specifies Gas Mark 3, set your conventional oven to 160-170°C. For a fan oven, the equivalent drops to 140-150°C. Some detailed charts split the difference with a convection adjustment column, placing 170°C conventional at the upper boundary of Gas Mark 3 or the lower boundary of Gas Mark 4 depending on rounding conventions (Wilprep Kitchen conversion chart).

Is 170 C equal to 350 F?

No — 350°F is actually closer to 177°C, not 170°C. The precise Fahrenheit equivalent of 170°C is 338°F, which is 12 degrees lower than 350°F (Flawless Food). This confusion arises because many recipe charts round to the nearest 25°F increment, making temperatures appear interchangeable when they are not.

Common misconceptions

US and UK recipe traditions sometimes use different rounding conventions. US recipes favour neat 25°F increments (325°F, 350°F, 375°F) for easy mental math, while UK references may use the more precise formula-based values or align with Gas Mark intervals. The result is that 170°C sometimes gets lumped with 350°F in casual recipe swaps, despite the 12°F gap.

Precise equivalents

For baking accuracy, use 338°F when a recipe specifies 170°C. If the recipe calls for 350°F and you need to replicate it in Celsius, set your oven to 177°C conventional or 157°C fan. These small differences matter most in delicate bakes like soufflés, meringues, and bread where precise gluten development or rising is temperature-dependent.

Comparison: Temperature Scales

The table below maps how three major temperature systems correspond across common baking settings.

The pattern is consistent: every 20°C reduction in a fan oven preserves roughly the same cooking effect as the conventional setting. For Gas Mark, each increment represents approximately 25-30°F, with Gas Mark 3-4 covering the most common baking range.

How to convert Celsius to Fahrenheit

Converting between temperature scales takes seconds once you know the formula. Whether you’re adapting a US recipe for an Australian oven or calculating the right fan oven reduction, the same two calculations cover every scenario.

Step 1: Apply the formula

• For Celsius to Fahrenheit: multiply by 9/5, then add 32
• For Fahrenheit to Celsius: subtract 32, then multiply by 5/9

Step 2: Adjust for oven type

• Fan oven: subtract 20°C from the conventional Celsius setting
• Conventional oven: use the exact conversion result

Step 3: Match to Gas Mark (UK ovens)

• Gas Mark 3 = 160-170°C conventional / 140-150°C fan
• Gas Mark 4 = 180°C conventional / 160°C fan
• Reference a conversion chart if your oven displays Gas Mark only

Step 4: Verify and adjust

• Use an oven thermometer to check actual cavity temperature
• Note that older ovens may run consistently hot or cold by 10-15°C
• Adjust recipe timing 5-10 minutes earlier for fan ovens

Fan ovens tend to cook food more evenly and quickly because they circulate hot air. Converting recipes from a regular electric oven without a fan to an electric fan oven is easy; reduce the heat by 20°C.

— Flawless Food (Recipe Blog)

These conversions are approximate rounding, and you may find your oven cooks quicker or slower than the standard suggests. Using an oven thermometer is the most reliable way to confirm your oven’s actual performance.

— Skint Chef (Recipe Site)

Related reading: 108 Inches to Feet Conversion

Recipes nearby on the dial, such as 190°C equaling 374°F with fan adjustments to 170°C, follow the same logic outlined in this 190°C to 374°F fan guide.

Frequently asked questions

For UK bakers following American recipes, the path from 338°F to the right oven setting requires two quick steps: convert the Fahrenheit to Celsius, then apply the fan oven reduction if needed. Most modern fan ovens handle the adjustment automatically via a convection setting, but knowing the 20°C rule gives you control when adjusting old recipes.