Prime Rib (Standing Rib Roast)
at 350°F
The answer
2 hr 40 min – 3 hr 30 minat 350°F
Plan on 20 to 26 minutes per pound in a 350°F oven. A 8 lb prime rib (standing rib roast) lands around 2 hr 40 min – 3 hr 30 min. Done is 145°F on a food thermometer, plus a 20-minute rest — never the clock alone.
SOURCE·USDA FSIS safe minimum internal temperatures·350°F planning range derived·REVIEWED JUL 2026
USDA safe zone — 145°F and above
Done is a temperature, not a time. Every figure on this page is a planning range; the green band is the only part that decides. For a bone-in prime rib it opens at 145°F and a 20-minute rest.
Source—USDA Food Safety & Inspection Service safe minimum internal temperatures—doneness bands per standard cooking references—retrieved 2026-07
How this is worked out
- Anchor. Start from what USDA FSIS publishes for a bone-in prime rib — its safe minimum internal temperature of 145°F, and the FSIS roasting timetable where one exists for this cut.
- Rate. Convert the anchor into a planning rate at 350°F: 20–26 min/lb, cross-checked against at least three independently published sources.
- Scale. Multiply that rate by your weight. A 8 lb piece lands at 2 hr 40 min – 3 hr 30 min; the range is widened to cover source disagreement rather than averaged into false precision.
- First check. The first thermometer reading is set at 85% of the low end of the range — early enough that an under-reading costs nothing and a late one cannot cost the meal.
- Gate. The time is only a plan. It is not done until a food thermometer reads 145°F in the thickest part, then rests about 20 minutes. Time never overrides temperature on this site.
- Round. Every printed figure is rounded to the nearest 5 minutes; precision beyond that would be invented.
plan_low = weight_lb × 20 min/lb
plan_high = weight_lb × 26 min/lb
first_check = plan_low × 0.85
DONE ⟺ internal_temp ≥ 145°F AND rest ≥ 20 min
(USDA FSIS — the gate, not the clock)
SOURCE·USDA FSIS safe minimum internal temperatures·safe minimum for this cut·REVIEWED JUL 2026
Time by weight at 350°F
Planning ranges for a fully thawed, fridge-temperature prime rib (standing rib roast). The right-hand column is when to take the first thermometer reading.
| Weight | Estimated time at 350°F | Check thermometer from |
|---|---|---|
| 4 lb | 1 hr 20 min – 1 hr 45 min | 1 hr 10 min in |
| 5 lb | 1 hr 40 min – 2 hr 10 min | 1 hr 25 min in |
| 6 lb | 2 hr – 2 hr 35 min | 1 hr 40 min in |
| 7 lb | 2 hr 20 min – 3 hr | 2 hr in |
| 8 lb | 2 hr 40 min – 3 hr 30 min | 2 hr 15 min in |
| 9 lb | 3 hr – 3 hr 55 min | 2 hr 35 min in |
| 10 lb | 3 hr 20 min – 4 hr 20 min | 2 hr 50 min in |
| 11 lb | 3 hr 40 min – 4 hr 45 min | 3 hr 5 min in |
| 12 lb | 4 hr – 5 hr 10 min | 3 hr 25 min in |
Start checking the internal temperature well before the low end of the range — an early check costs nothing; a late one costs the meal. Done means 145°F on a food thermometer.
SOURCE·USDA safe-temperature guidance·timing ranges derived, see method·REVIEWED JUL 2026
350°F vs the other temperatures
Same cut, every temperature this site publishes for it.
| Oven temp | Time for a 8 lb prime rib (standing rib roast) | Per pound |
|---|---|---|
| 325°F | 3 hr 5 min – 4 hr | 23–30 min/lb |
| 350°F (this page) | 2 hr 40 min – 3 hr 30 min | 20–26 min/lb |
SOURCE·USDA safe-temperature guidance·timing ranges derived, see method·REVIEWED JUL 2026
When it is actually done
145°F internal
The USDA FSIS safe minimum internal temperature for this cut is 145°F, followed by a rest of about 20 minutes. The clock estimates; the thermometer decides. Every time on this page is a planning range, not a doneness test.
SOURCE·USDA FSIS safe minimum internal temperatures·prime rib (standing rib roast) row of the FSIS chart·REVIEWED JUL 2026
Doneness temperatures
| Doneness | Internal temp | |
|---|---|---|
| Rare | 120–125°F | below the USDA minimum |
| Medium-rare | 130–135°F | below the USDA minimum |
| Medium | 135–145°F | |
| Medium-well | 145–155°F | |
| Well done | 155°F+ |
USDA FSIS recommends a minimum of 145°F with a 20-minute rest for whole cuts. Rare and medium-rare sit below that guideline — a personal choice many cooks make with fresh, well-handled meat, listed here because these are the temperatures cookbooks and restaurants use.
SOURCE·Standard published cooking references·doneness bands·REVIEWED JUL 2026
The clock tells you when to start looking. The thermometer tells you when to stop.
What the ledger does not tell you
- The low end of each range lands medium-rare, the high end medium — decide your pull temperature before you start, not at the oven door.
- A large roast carries over 5–10°F while resting; pull it that far below your target.
- Many cooks finish with a 500°F blast for the last 8–10 minutes (or start with one) for the crust — the per-pound time barely changes.
- Bones act as insulation: a boneless ribeye roast of the same weight cooks slightly faster.
Answers people ask
How long does a bone-in prime rib take at 350°F?
Plan on 20 to 26 minutes per pound at 350°F. A 8 lb example takes about 2 hr 40 min – 3 hr 30 min. It is done when the internal temperature reaches 145°F on a food thermometer, not when the clock runs out.
What internal temperature is a bone-in prime rib done at?
145°F, measured with a food thermometer in the thickest part, then rested about 20 minutes. That is the USDA FSIS safe minimum.
Is 350°F a good temperature for a bone-in prime rib?
It is one of 2 temperatures this site publishes for this cut (325°F, 350°F). Lower runs longer and more forgiving; higher runs faster with more browning. 325°F is the most common choice.
SOURCE·USDA FSIS safe minimum internal temperatures·doneness figures quoted in these answers·REVIEWED JUL 2026
Where these numbers come from
Ranges are anchored to USDA FSIS published timetables where they exist, and derived from that anchor plus cross-checked published sources where they do not — widened to cover the disagreement between sources rather than split down the middle. The full reasoning is on the method page. If a figure here looks wrong, say so — corrections are prioritised.
SOURCE·USDA safe-temperature guidance·timing ranges derived, see method·REVIEWED JUL 2026
