This level will tend to fluctuate throughout the course of a day, with the lowest readings during periods of fasting and the highest coming shortly after a meal. The normal blood sugar range for a healthy person is about 83 mg/dl (4.6 mmol/L) to 120 mg/dl (6.6 mmol/L). A healthy person's body is able to regulate blood glucose levels very tightly, resulting in a predictable normal blood sugar range.