Target blood sugar levels for people with controlled diabetes range from 70 to 180 depending on the time of day and the time since their most recent meal, according to WebMD. Blood sugar levels are at their lowest before meals and are highest within one to two hours of eating.
Blood sugar levels of 240 or more indicate uncontrolled diabetes, according to the University of Washington Center for Women's Health. Blood sugar levels in excess of 300 pose an immediate danger and require medical attention. Conversely, diabetics who have blood sugar levels of 70 or lower are at risk for hypoglycemia.