It can take up to 30 minutes to bake chicken breasts. The exact length of time depends on the size of the chicken and the oven temperature.
An average sized chicken breast should cook for approximately 20 minutes at a temperature of 400 degrees Fahrenheit. If the temperature of the oven is lower, the chicken needs to cook for an additional 10 to 15 minutes. Larger chicken breasts may also require additional cooking time. When a chicken breast is thoroughly cooked, it should reach an internal temperature of 170 degrees F. To check the temperature, users should insert a meat thermometer into the thickest part of the breast.