Essentials.Fitness

Ideal Weight & Body Fat Calculator

Record your current body values. Fields marked with * are required to calculate ideal weight, BMI and body fat.

Note: These metrics are only rough guidelines and do not replace individual advice.

Body Fat & Measurements

How does the calculator work?
  1. Enter your height and weight
  2. Select your gender
  3. Read your BMI and ideal weight
  4. Optional: Switch to detailed mode for all 8 formulas
  5. Enter waist circumference for WHtR and RFM (body fat)
  6. Optional: Hip circumference for WHR and all measurements for later comparison
  7. Save your status as PDF or JSON

The calculator uses scientifically validated formulas like BMI, Devine, WHtR, and RFM.

What is ideal weight?
Ideal weight is a theoretical value based on various formulas. There is no universal definition - different formulas (BMI, Devine, Broca) yield different results.
Which formula is most accurate?
For most people, the Devine formula is most relevant as it is used in medicine for dosage calculations. BMI is the most widespread but not suitable for everyone (e.g., athletes).
What does WHtR tell you?
The Waist-to-Height Ratio (WHtR) measures abdominal fat. A value below 0.5 is considered healthy. It is more meaningful than BMI as it considers fat distribution.
How accurate is body fat calculation?
The formulas (RFM, US Navy) provide estimates with about 3-5% deviation. For precise values, DEXA scans or caliper measurements are required.
What is the difference between BMI and RFM?
BMI only considers weight and height. RFM (Relative Fat Mass) also includes waist circumference and estimates body fat percentage more accurately.
Can I save my data?
Yes! You can export your current status as PDF or save it as a JSON file. This way you can reload your values later and compare your progress.
How is the data calculated?

The calculator uses various established formulas to estimate body mass index, ideal weight and body fat. All values are references and do not replace medical advice.

BMI – Body Mass Index

BMI = weight (kg) / height² (m)

Ponderal Index (PI)

PI = weight (kg) / height³ (m)

Devine (1974) – Ideal Weight

Men: 50 + 2.3 × (in − 60) kg
Women: 45.5 + 2.3 × (in − 60) kg

Hamwi (1964) – Ideal Weight

Men: 106 lb + 6 lb × (in − 60)
Women: 100 lb + 5 lb × (in − 60)

Robinson (1983) – Ideal Weight

Men: 52 + 1.9 × (in − 60) kg
Women: 49 + 1.7 × (in − 60) kg

Miller (1983) – Ideal Weight

Men: 55.7 + 1.39 × (in − 60) kg
Women: 53.0 + 1.33 × (in − 60) kg

Broca (1871)

Normal weight = height (cm) − 100
Ideal weight: men −10%, women −15%

Lorentz – Ideal Weight

Men: (cm − 100) − (cm − 150)/4
Women: (cm − 100) − (cm − 150)/2

WHtR – Waist-to-Height Ratio

WHtR = waist / height

WHR – Waist-to-Hip Ratio

WHR = waist / hip

BAI – Body Adiposity Index

BAI = hip (cm) / height^1.5 (m) − 18

RFM – Relative Fat Mass (2018)

Men: 64 − 20 × (height / waist)
Women: 76 − 20 × (height / waist)

US Navy – Body Fat Formula

Men: 495 / (1.0324 − 0.19077 × log₁₀(waist − neck) + 0.15456 × log₁₀(height)) − 450
Women: 495 / (1.29579 − 0.35004 × log₁₀(waist + hip − neck) + 0.221 × log₁₀(height)) − 450

Ideal weight formulas provide reference weights and do not replace individual assessment. Screening metrics like BMI, WHR or RFM do not account for body composition or health factors in detail. If unsure, consult medical professionals.