What is an average blood sugar reading?

Most people without diabetes have a blood sugar reading of 70 to 80 mg/dL, or milligrams per tenth of a liter of blood, before meals, according to WebMD. People with untreated diabetes or prediabetes typically have much higher blood sugar readings.

A blood sugar reading of less than 100 mg/dL is normal for someone who has fasted for several hours, explains WebMD. Up to 140 mg/dL is normal two hours after eating a meal. A blood sugar reading of more than 126 mg/dL after fasting for eight hours means a person can be diagnosed with diabetes. A blood sugar reading of less than 60 mg/dL is very unusual.