What health calculators are available on Calc4Health?

Calc4Health offers 17+ professional health calculators including BMI, BMR, TDEE, body fat percentage, target heart rate, daily water intake, waist-hip ratio, Cooper test, relative fat mass, body surface area, body adiposity index, body shape index, conicity index, heart rate zones, new BMI Trefethen calculator, Blood Alcohol Content (BAC) calculator, and Dietary Reference Intake (DRI) calculator.

Are Calc4Health calculators free to use?

Yes, all health calculators on Calc4Health are completely free to use. No registration or payment required. Access professional medical calculation tools instantly for your health and fitness monitoring needs.

How accurate are the health calculators?

Calc4Health calculators use scientifically validated formulas and equations from medical research. They provide accurate estimates based on established medical standards, though results should be used for reference and not replace professional medical advice.

What is RFM and how is it different from BMI?

RFM (Relative Fat Mass) directly estimates body fat percentage using height and waist measurements. Unlike BMI, which uses weight, RFM better distinguishes between muscle and fat mass, making it more accurate for athletic individuals.

Is RFM more accurate than BMI?

Yes, studies show RFM correlates better with DXA scan results (gold standard) than BMI. RFM was developed in 2018 and validated on over 12,000 adults, showing superior accuracy in predicting body fat percentage.

How do I measure my waist for RFM calculation?

Measure your waist at the top of the hip bone, typically at navel level. Stand relaxed, breathe out normally, and wrap the tape measure horizontally around your waist. Keep the tape snug but not compressing the skin.

Relative Fat Mass (RFM) Calculator

Calculate your RFM using height and waist circumference. A more accurate alternative to BMI for estimating body fat percentage and obesity risk.

Patient Measurements

Height

Waist Circumference

Measure at navel level, after exhaling normally

Gender

RFM Result

Enter your measurements to calculate RFM

RFM Advantages

RFM is more accurate than BMI for predicting body fat percentage. Studies show it better identifies obesity and related health risks.

Clinical Research

Validated by clinical studies showing superior prediction of metabolic syndrome and cardiovascular risks.

Measurement Tips

Measure waist at navel level after normal exhalation. Stand straight for height measurement. Use same units for both.

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RFM Formula

RFM = 64 - (20 × height/waist) + (12 × sex)
where sex = 0 for men, 1 for women

Men's Formula

RFM = 64 - (20 × height/waist)

Women's Formula

RFM = 76 - (20 × height/waist)

Obesity Thresholds

Men: RFM ≥ 22.8%
Women: RFM ≥ 33.9%

Medical Reference

Scientific Research Reference

Woolcott, O.O., Bergman, R.N. (2018). Relative fat mass (RFM) as a new estimator of whole-body fat percentage ─ A cross-sectional study in American adult individuals. Sci Rep 8, 10980.

View Publication DOI

Author

Dr. Beltrán J.F.