A normal estimated GFR ranges from 90 to 120 milliliters per minute per 1.73 square meters, according to MedlinePlus. Because normal GFR ranges vary depending on the laboratory, sample and measurements used, it's best to discuss individual results with a doctor.
The formula used to calculate a patient's GFR includes factors such as age, ethnicity, creatinine level, gender, and height and weight, explains MedlinePlus. The GFR, or glomerular filtration rate, indicates how well the kidneys are filtering waste from the blood. GFR levels less than 60 for three months or more sometimes indicate chronic kidney disease. A patient with a GFR less than 15 is usually experiencing kidney failure, which warrants immediate medical care.