WebMD offers a simple chart on its website showing target blood sugar levels for diabetics before and after meals, after fasting, before exercise and before bed. Normal blood glucose levels when fasting are under 100 milligrams per deciliter, according to WebMD.
Blood glucose levels measured one to two hours after a meal should be under 180 milligrams per deciliter, states WebMD. Levels before a meal should range from 70 to 130 milligrams per deciliter. Diabetics should strive for a blood glucose reading between 100 and 140 milligrams per deciliter before bedtime. Testing and recording blood sugar levels on a regular basis helps measure the success of treatment and encourages proper management of diabetes.