Why TDEE Lab shows a range
Formula comparison is more honest than a single target. Each equation uses a different height-based assumption, so the range shows how much the estimates can disagree.
What these formulas miss
They do not account for muscle mass, bone structure, age, training history, or health context. Pair this page with TDEE and body-composition tools for a fuller starting point.
Calculation method
Calculator method: Height is converted to inches, then h is set to inches above 5 feet. Devine uses 50 + 2.3h kg for the male reference option and 45.5 + 2.3h kg for the female option. The conventional rounded Robinson form uses 52 + 1.9h kg and 49 + 1.7h kg. Miller uses 56.2 + 1.41h kg and 53.1 + 1.36h kg. Hamwi uses 106 + 6h lb and 100 + 5h lb, then converts pounds to kilograms.
These equations were created as simple height-based reference weights. The Devine equation began as a way to estimate drug dosing weight, not as a definition of a healthy or attractive body weight. Later equations changed the constants but kept the same basic linear structure.[1]
The Robinson equation was proposed for drug dosage calculations using height and a male or female reference branch.[2] The original regression paper reports 51.65 + 1.85h kg and 48.67 + 1.65h kg. This calculator uses the commonly published rounded version shown above. Modern analyses show that the older equations can produce systematic differences across height and should not be treated as universal standards.[3]
How the comparison is built
TDEE Lab calculates all four values for the selected height and historical sex branch. The displayed range is the lowest through highest result. The average is the arithmetic mean of the four results, and the spread is the maximum minus the minimum. The average is a summary of the formulas. It is not a more accurate fifth formula.
The implementation does not allow any formula result below 20 kg. This is a software guard. It is not a clinical lower boundary. The original equations are generally expressed for adults at least 5 feet tall. For shorter heights, this calculator extends the linear equations below their usual reference point and applies the 20 kg guard. Treat those outputs as especially uncertain.
The male and female controls select the two coefficient sets used in the historical publications. They do not assess sex, gender, hormones, body composition, or medical status. Choose the branch that is useful for comparing the published equations, then interpret the result with current personal context.
Important limitations: These formulas use only height and a historical sex branch. They ignore age, muscle mass, fat distribution, bone structure, ethnicity, disability, pregnancy, training status, health conditions, and personal goals. A person can be healthy above or below the displayed range. The results must not be used to diagnose health, prescribe weight loss, calculate medication doses, or define a required target. For nutrition planning, use current weight and observed trends with the
TDEE calculator. Use the
body composition calculator only as an additional screening estimate.
Research sources
- Historical review Pai MP, Paloucek FP. The Origin of the Ideal Body Weight Equations. Annals of Pharmacotherapy, 2000. View the publication record. Reviews the origins and intended uses of the Devine, Robinson, Miller, and Hamwi equations. Back to text
- Primary research Robinson JD, Lupkiewicz SM, Palenik L, Lopez LM, Ariet M. Determination of ideal body weight for drug dosage calculations. American Journal of Hospital Pharmacy, 1983. View the PubMed record. Presents the Robinson equation in its drug-dosing context. Back to text
- Primary analysis Peterson CM, Thomas DM, Blackburn GL, Heymsfield SB. Universal equation for estimating ideal body weight and body weight at any BMI. American Journal of Clinical Nutrition, 2016. Read the open-access study. Compares historical formulas and explains height-related bias and the limits of a single ideal weight. Back to text
Frequently asked questions
Is this my perfect weight?
No. The calculator shows historical reference formulas, not medical targets or personalized prescriptions.
Which formula should I trust?
Use the formula comparison as context. The spread can be more useful than choosing one equation as correct.
