How long to bake a sweet potato depends mostly on the oven temperature and the size of the potato. Clemson, Montana State and Iowa State Extension all give 400°F for baking whole sweet potatoes, and a medium one takes about 45 minutes. Here is what these and other Extension programs say about oven times, microwave and boiling times, roasting cut pieces, how to tell when it is done and how to store the leftovers.
The short answer: bake a medium sweet potato at 400°F for about 45 minutes, until it is soft or tender. Clemson says 40 to 50 minutes, Montana State says 45 minutes and Iowa State says 45 minutes to 1 hour. Prick the skin first so steam can escape. Smaller potatoes need less time and larger ones need more, so start checking early.
How long to cook a sweet potato, by method
Method
Time
Source
Oven, 400°F, whole
40 to 50 minutes until soft
Clemson
Oven, 400°F, medium
About 45 minutes
Montana State
Oven, 400°F, whole
45 minutes to 1 hour until tender
Iowa State
Microwave, high
4 to 6 minutes for one 8-ounce sweet potato
Clemson
Microwave
5 to 8 minutes, rotating and flipping halfway
Iowa State
Microwave, high
5 to 7 minutes for a medium one, turned over once
Montana State
Boiled whole
30 to 45 minutes depending on size
Clemson
Boiled whole or cut up
30 to 40 minutes whole, 20 to 30 minutes cut up
Montana State
Fries cut into ½-inch strips, 450°F
About 25 minutes on a parchment-covered baking sheet, turning halfway
Montana State
The sources overlap but are not identical. Sweet potatoes vary in size and shape, and Clemson notes that times vary with size. Use the range as a guide, then check for doneness. Details are from Clemson Cooperative Extension’s sweet potato factsheet (revised 2022), Iowa State University Extension’s SpendSmart guide and Montana State University Extension’s sweet potato factsheet.
How to bake a sweet potato in the oven
Pick sound sweet potatoes. See our guide to how to pick a good sweet potato. Keep them out of the fridge beforehand, since cold can harden the center. Our guide to whether sweet potatoes need to be refrigerated explains why.
Wash and prick. Montana State says to wash sweet potatoes to remove dirt and to poke them with a fork 3 to 4 times to let steam escape. Clemson and Iowa State also say to prick the skin. Iowa State says to pierce it 5 to 6 times.
Bake at 400°F. Place them on a baking sheet. Iowa State lines the sheet with foil.
Bake until soft. Clemson says until soft, and Iowa State says until tender. Start checking at about 40 minutes for a medium potato.
In American recipes, “yams” usually means soft orange sweet potatoes, which you bake the same way. True yams are a different vegetable. See our guide to sweet potato vs yam.
How long to roast cut-up sweet potatoes
Cut pieces cook faster than whole potatoes. These are recipe-specific times, not universal standards, because the recipes use different cuts, temperatures and added ingredients. Oregon State Un
