The time it takes to cook waffles in a waffle maker depends on the brand and model of the waffle iron. There are several signs you can look for, however, to determine when your waffles are done.
Most waffle irons have some sort of indicator to notify you when the waffle is cooked, such as a light that turns off when the waffle is done or an alarm that beeps.
If your waffle iron doesn't have an alarm or light, check the owner's manual--which should contain guidelines for how long to cook waffles--and use a timer.
If you don't have a light, alarm or owner's manual, cook a test waffle until the batter stops steaming, timing the cooking with a stopwatch. This waffle will probably be well-done, but now that you know the cooking time, you can adjust it for later waffles.
If you try to lift the waffle maker's lid before the waffle is done, the waffle might stick and rip. You may need a few test waffles to figure out the best cooking time.