170°C — all four oven scales
The exact conversion is °C × 9/5 + 32, so 170°C works out to 338°F. 170°C sits between the rows of the standard gas-mark table used here rather than on one, so this page doesn't claim a recipe pairing for it. An American oven with a 25°F dial gets closest at 350°F, 12°F above the exact figure; a digital oven can take 338°F directly.
For a conventional recipe in a fan (convection) oven, use 150°C — the standard UK adjustment is conventional minus 20°C (a 36°F difference), because moving air transfers heat faster than still air; the oven isn't hotter than its dial, it just cooks faster at the same setting. Hoover also says long cooking times can be shortened by up to 10 minutes per cooking hour — check the food is cooked. Bake times are otherwise unaffected by converting between scales: 170°C is 338°F whichever unit your dial shows.
Where 170°C sits on the chart
| °F | °C | Fan °C | Gas mark | Descriptor |
|---|---|---|---|---|
| 300°F | 150°C | 130°C | 2 | Slow |
| 325°F | 160°C | 140°C | 3 | Moderately slow |
| 350°F | 180°C | 160°C | 4 | Moderate |
| 375°F | 190°C | 170°C | 5 | Moderately hot |
| 400°F | 200°C | 180°C | 6 | Moderately hot |
See the full chart on the oven temperature converter → · Fan oven conversion chart →
What bakes at this temperature
170°C / 338°F is the territory of cheesecakes, shortbread and gentle sponges. Home ovens cycle above and below their set point and many run hot or cold from the factory — a standalone oven thermometer on the middle rack tells you more than any conversion chart can.