Health & Fitness Calculators

No. They are educational estimates based on the method and reference data named on each page. Measurement error, population limits, medications, pregnancy, illness, and other clinical factors can change interpretation. Confirm results with a qualified healthcare professional.

According to the American Diabetes Association, an A1C below 5.7% is considered normal. A level between 5.7% and 6.4% indicates prediabetes and warrants lifestyle changes. An A1C of 6.5% or higher on two separate tests indicates diabetes. People actively managing diabetes typically aim to keep their A1C below 7.0%, though target levels should be individualized with a doctor.

A period calculator projects dates from the last start date and an assumed average cycle length. Natural cycle variation, stress, illness, postpartum changes, hormonal contraception, and conditions such as PCOS can shift timing, so it should not be used as contraception or as a diagnostic tool.

The traditional Payne equation estimates an albumin-adjusted calcium value: measured calcium + 0.8 × (4.0 − albumin), using mg/dL and g/dL. Its accuracy varies by patient population and laboratory method, and direct ionized-calcium measurement may be more appropriate clinically.