As of 2015, WebMD offers a blood glucose level chart showing optimal blood sugar levels as part of its diabetes health center, according to the resource's website. Healthline offers a blank printable blood sugar chart for patients who want to track their blood glucose levels at home, reports the website.
Optimal blood glucose levels for adults age 20 and older are less than 100 when fasting, 70 to 130 before meals, and less than 180 after meals, according to WebMD. Blood glucose levels should be at least 100 before exercise for diabetics who are taking insulin, and between 100 and 140 before bed. Well-managed diabetes prevents or delays complications, such as heart disease, stroke or kidney disease.