How the conversions work
By AnoyUpdated Last reviewed How we calculate
Every conversion on Oven to Air Guide comes from one short set of rules, published in full below. Into the air fryer: lower the oven temperature by 25°F (15°C), round to the nearest 5°, and multiply the time by 0.8. The same code produces the calculator, every chart and the printable PDF, so they can never disagree. Current method version: 1.1.
The formulas
| Conversion | Temperature | Time |
|---|---|---|
| Conventional, gas or toaster oven → air fryer | − 25°F / − 15°C | × 0.8 (by food type, below) |
| Air fryer → conventional oven | + 25°F / + 15°C | × 1.25 |
| Convection / fan oven → air fryer | No change | × 0.9 |
| Air fryer → convection / fan oven | No change | × 1.1 |
| Food type (oven → air fryer) | Time multiplier |
|---|---|
| Most recipes | × 0.8 |
| Thin and crispy (fries, cutlets, fish fillets) | × 0.75 |
| Vegetables | × 0.75 |
| Thick meat and roasts | × 0.85 |
| Cakes and bakes | × 0.85 |
| Frozen packaged food | × 0.8 |
Rounding and the “check at” time
- Temperatures are rounded to the nearest 5 degrees, because that is how air fryer and oven dials step.
- Times are rounded to the nearest whole minute, never below 1 minute.
- Into the air fryer, “check at” = original oven time × 0.75, rounded down. Into the oven, it is 90% of the converted time.
- Unit conversions use the exact formulas: °C = (°F − 32) × 5/9 and °F = °C × 9/5 + 32.
Worked example
400°F for 25 minutes in a conventional oven: 400°F − 25°F = 375°F · 25 min × 0.8 = 20 min · check at 18 min. Converting that result back to the oven gives 400°F for 25 minutes, the original recipe. The two directions are exact inverses.
Input limits and warnings
- The calculator accepts 150–550°F (65–290°C) and 1–600 minutes.
- A warning appears when the converted setting is above 400°F (200°C), below 250°F (120°C), or when the original cook is over an hour.
Why these numbers
Lower the temperature. An air fryer is a small convection oven with a strong fan. Moving air strips away the cooler layer of air that sits on food in a still oven, so heat transfers faster and the surface browns at a lower setting. Reducing by about 25°F is the widely used rule of thumb for this, and it matches the adjustment recipes make for convection ovens. In Celsius, 25°F is 13.9°C; the site uses 15°C so results land on 5-degree dial steps.
Shorten the time by about 20%. Faster heat transfer and a much smaller, quicker-to-heat chamber mean food reaches the same doneness sooner. Thin foods with lots of surface (fries, cutlets) gain the most, so they use × 0.75. Thick meat and cakes are limited by how fast heat travels to the center, which the fan barely changes, so they use × 0.85.
Convection keeps the temperature. A convection or fan oven already uses moving air, so recipes written for it have already been adjusted. The air fryer’s smaller chamber and closer element still make it a little faster: × 0.9.
Check at 75%. Air fryers differ a lot by model, so the site always gives an early check time. Opening the basket early costs nothing; overcooked food can’t be fixed.
Sources and data
- Safe internal temperatures: FoodSafety.gov safe minimum internal temperatures (USDA/FDA). Used on every food page and in the calculator tips.
- Gas marks: the standard UK gas mark table (1 = 140°C, 2 = 150°C, 3 = 170°C, 4 = 180°C, 5 = 190°C, 6 = 200°C, 7 = 220°C, 8 = 230°C, 9 = 240°C).
- Air fryer maximum: 400°F (200°C) is a common upper limit for basket air fryers; check your manual for yours.
- Food pages: oven directions are typical package or recipe directions for that food; air fryer directions are converted with the formulas above. Where the general rule is a poor fit (for example small frozen snacks), the page says so and shows both numbers.
How accuracy is checked
- One source of truth. All formulas live in one file. The calculator, the HTML charts (generated when the site is built) and the printable chart all call it, so a table can’t drift away from the calculator.
- Inverse check. Converting into the air fryer and back returns the original recipe.
- Shown working. Every result prints its arithmetic (for example “400°F − 25°F = 375°F · 25 min × 0.8 = 20 min · check at 18 min”) so you can check it yourself.
- Visible review dates. Each page shows when it was last reviewed; see below.
Limitations
The arithmetic is exact. The cooking outcome is an estimate. In particular:
- Air fryers differ in wattage, basket size and element distance, so real cooking times vary by model.
- A full or stacked basket cooks more slowly than a single layer.
- Wet batters, delicate cakes, low-and-slow recipes and large roasts don’t convert reliably with any simple formula.
- Times never guarantee food safety. Use a thermometer.
Updates, reviews and corrections
- Updated on a page means its content changed on that date.
- Last reviewed means Anoy re-checked the page’s numbers against these formulas and sources and confirmed they are still right, even if nothing changed. Pages are due for review every 180 days.
- Method version changes only when a formula or multiplier changes. Every change is recorded in the change log.
- Corrections: email hello@oventoairguide.com with the page and the numbers you entered. See the editorial policy for how corrections are handled.