Cooking time from weight gets you a plan, but a food thermometer gets you a safe, perfectly-cooked roast. This guide shows how the estimates are built, why internal temperature beats the clock, and how to back-time your cook so everything is ready when you want to eat.

How cooking time is estimated

The calculator multiplies the weight of the whole bird or roast by a minutes-per-pound rate that depends on the meat, the oven temperature, and — for poultry — whether it is stuffed. For example, an unstuffed turkey at 325°F runs about 13 minutes per pound, while a stuffed bird runs closer to 15. Higher oven temperatures lower the per-pound rate but can dry the surface before the center finishes, which is why 325°F is the classic choice for large turkeys.

These rates are roasting guidance compiled from USDA and common test-kitchen charts. Real ovens vary by 25°F or more from their dial, and a flat roast cooks faster than a compact one of the same weight, so treat the time as a planning estimate, not a guarantee.

Why internal temperature wins

Time tells you when to start checking; temperature tells you when it is done. The USDA safe minimum internal temperatures are 165°F for all poultry, 145°F for whole cuts of beef, pork, lamb, and veal (with a 3-minute rest), and 160°F for ground meats. Insert the thermometer into the thickest part — for a turkey, the inner thigh away from the bone — and trust the reading over the clock.

Carryover cooking matters here: a big roast keeps rising 5–15°F after it leaves the oven, so pulling beef a few degrees early and letting it rest yields a more even result.

Back-timing, stuffing, and thawing

To serve at a set time, work backward: subtract the cook time, the rest, and a carving buffer from your target. The Start-Time Planner does this for you. Stuffing a bird adds time and a food-safety wrinkle — the center of the stuffing must also reach 165°F, so many cooks bake it separately. Finally, plan your thaw: in the refrigerator, allow about 24 hours per 4–5 pounds, so a 14 lb turkey needs roughly three days. Never thaw meat on the counter, where the surface enters the bacterial danger zone before the center thaws.

When in doubt, give yourself a buffer. A roast that finishes early can rest longer under foil; a roast that finishes late holds up the whole meal.