How Long to Bake Chicken Breast at 400°F
Bake chicken breast at 400°F for about 18–35 minutes depending on size, then verify 165°F in the thickest part before serving.
Quick reference
- Small breast: 18–22 minutes About 5–6 oz
- Medium breast: 22–28 minutes About 7–9 oz
- Large breast: 28–35 minutes 10 oz or more
- Safe endpoint: 165°F / 74°C Check the thickest part
How long to bake chicken breast at 400°F
For boneless, skinless chicken breasts, bake at 400°F for about 18–35 minutes, depending mainly on thickness and weight. Small breasts usually finish in 18–22 minutes, medium breasts in 22–28 minutes, and large breasts in 28–35 minutes. These are starting ranges, not guarantees: ovens, pans, starting temperature, and breast shape can change the timing. Begin checking early rather than relying on the clock alone.
Use thickness, not just size
A thick breast can take longer than a heavier, flatter one. For more even cooking, place each breast between sheets of plastic wrap or parchment and gently pound the thickest section until the meat is fairly uniform—about ¾ inch thick. Avoid flattening it paper-thin. If the chicken is frozen, thaw it safely in the refrigerator before baking; do not thaw raw chicken on the counter.
Prepare the pan for even baking
Pat the chicken dry, season it, and arrange the pieces in a single layer in a lightly oiled baking dish or rimmed sheet pan. Leave a little space between breasts so hot air can circulate and moisture does not collect between them. Crowded chicken may cook less evenly. If pieces vary greatly in thickness, give the larger ones a head start or pound them to match.
Check for 165°F, not color
The dependable test is an instant-read thermometer inserted into the thickest part of the largest breast, with the tip away from the pan. Chicken is ready when it reaches 165°F (74°C). Do not judge doneness by the outside color or by clear juices; both can be misleading. If the chicken is below 165°F, return it to the oven and check again after a few minutes.
Rest before slicing
Transfer the baked chicken to a plate or cutting board and rest it for about 5 minutes before slicing. This gives the juices time to settle and makes the meat easier to cut neatly. If you are cooking several breasts, check each piece because they may finish at different times. Refrigerate leftovers within 2 hours and use them within 3–4 days.