A good rule of thumb for a 20‑pound turkey at 325°F (163°C) is about 4½–5 hours, but you should always go by internal temperature: the turkey is done when the thickest part of the thigh reaches 165°F (74°C) and the juices run clear.

Oven time guidelines

• For an unstuffed 20 lb turkey at 325°F, plan roughly 4–4½ hours, checking with a meat thermometer starting around the 4‑hour mark.

• For a stuffed 20 lb turkey at 325°F, plan closer to 4½–5 hours, since stuffing slows cooking in the cavity.

Temperature and safety

• The safest and most reliable indicator is internal temperature: aim for 165°F in the thickest part of the thigh and breast, avoiding the bone.

• Let the turkey rest 20–30 minutes loosely tented with foil before carving so the juices redistribute and the temperature evens out.

Quick reference table

Turkey (20 lb)| Oven temp| Stuffed?| Approx. cook time| Doneness check
---|---|---|---|---
20 lb turkey| 325°F| Unstuffed| 4–4½ hours17| 165°F in thigh and breast38
20 lb turkey| 325°F| Stuffed| 4½–5 hours359| 165°F in thigh, breast, and stuffing center38

If your oven runs hot or cold, start checking 30–45 minutes earlier than the low end of the range, and leave extra time in your schedule in case it needs longer.