Learning how long to cook a turkey in a convection oven may take some adjustments on your part. There are a number of things to consider when determining cooking times. Take the following into account when cooking a turkey in a convection oven.

Is the turkey stuffed? Stuffed turkeys take longer to cook to bring the stuffing up to a safe serving temperature and avoid food poisoning.
What size is the turkey? The larger the turkey, the longer it will need to be cooked.
Are you cooking a whole turkey or just a turkey breast? Turkey breast meat cooks more quickly than dark meat, so if you are cooking a breast only, it will take less time to cook the meat to a safe temperature.
Will you be cooking the turkey in a bag? Cooking turkey in a poultry bag further reduces the cooking time. Check the bag manufacturer's instructions for specific cooking times.
How often will you be basting the turkey? Every time you open the oven to baste the turkey, the temperature of the oven drops slightly. This can lead to slightly longer cooking times if you baste often. Use a turkey thermometer to assure the turkey has been cooked to a safe temperature.
How dark is your roasting pan? A darker roasting pan will generally cook food more quickly than a shiny metal pan.

Safe Temperatures
The time it takes to cook a turkey is the time it takes for the turkey to reach a "safe" temperature where the danger of food-borne illnesses is minimized. The internal temperature of a turkey should reach 165°F for the turkey to be considered safe. Measure temperature at the thickest part of the turkey's thigh, making sure the meat thermometer doesn't touch the bone of the turkey. Stuffing should also reach 165°F.