To roast potatoes at 400°F, the roasting time generally ranges between 30 to 45 minutes. For 1-inch potato pieces, the typical roasting time is around 30 minutes. If the potatoes are cut smaller, like 1/2 inch pieces, roast them for about 25 minutes, then flip and roast for an additional 15-20 minutes until tender and browned well. For larger or more rustic cuts (about 1 1/2 inch pieces), roasting can take closer to 40-45 minutes, tossing halfway through for even cooking. In summary, roasting potatoes at 400°F typically takes:

• About 30 minutes for 1-inch cubes,
• 40-45 minutes for larger chunks,
• 40-45 minutes with a toss halfway for even browning,
• Or a two-step process for smaller pieces totaling around 40-45 minutes.

This ensures crispy outside and tender inside potatoes roasted at 400°F.