A whole turkey cooked at 250°F generally takes about 15–20 minutes per pound , but you must rely on internal temperature, not time alone, to be safe.

Safe time and temperature

  • Plan roughly 15–20 minutes per pound at 250°F for an unstuffed turkey. For example, a 12 lb bird would take about 3–4 hours, while a 20 lb bird might take 5–6 hours.
  • The turkey is done when the breast reaches 165°F and the thigh reaches about 175°F on a meat thermometer, regardless of the clock.
  • Stuffed turkeys or very large birds can take longer and are harder to cook safely at low temperature, so many guides recommend cooking them unstuffed and baking stuffing separately.

Basic low-and-slow method

  • Thaw the turkey completely in the fridge for several days (up to 5–6 days for a 20+ lb bird) and pat it dry.
  • Season and place it breast‑side up on a rack in a roasting pan; tent loosely with foil to prevent over‑browning.
  • Roast at 250°F, checking internal temperature once you reach the minimum estimated time (15 minutes per pound), then continue until it hits safe temps.
  • Let the turkey rest about 30 minutes before carving so the juices redistribute.

Example times at 250°F

Here is a typical time range many low‑temp turkey guides give for 250°F. Always verify with a thermometer rather than relying only on this chart.

Turkey weight Approx. cook time at 250°F
10 lb 2.5 – 3 hours
12 lb 3 – 3.5 hours
14 lb 3.5 – 4 hours
16 lb 4 – 4.5 hours
18 lb 4.5 – 5 hours
20 lb 5 – 6 hours
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Quick safety notes

  • Use an oven thermometer to confirm your oven truly holds 250°F, since low‑temp cooking leaves less margin for error.
  • If in doubt, increase the oven to a more standard 325–350°F once the turkey is close to done to crisp the skin and pass through any “danger zone” more quickly.

Bottom line: calculate 15–20 minutes per pound at 250°F, but pull the turkey only when the breast hits 165°F and the thigh about 175°F on a reliable thermometer.