Historical Weight Equation Comparison

This calculator compares Devine, Robinson, Miller and Hamwi height-based equations. The formulas are documented in Table 3 of a paper coauthored by researchers at Harvard Medical School and other institutions. They produce reference outputs, not a measured ideal weight or personal health verdict. Published formula table

The page retains the familiar “ideal weight” search term while showing what is actually calculated. It takes height and the sex-specific equation category; there is no frame-size input, body-fat measurement or assessment of your fitness, diet or health.

How to Calculate Ideal Body Weight

Select the units before entering height, then choose the sex-specific equations. This comparison is restricted to heights of at least 60 inches (152.4 cm). The published discussion expresses the height term above five feet, and the website does not extend it below that boundary. Height convention

In metric mode, the site divides centimeters by 2.54 to obtain inches. It then subtracts 60 from that height for the formulas below. The output cards show kilograms and a rounded conversion to pounds. They do not rank the formulas by personal accuracy.

Changing units clears the entered height and any earlier result. Check the new unit label before entering another number. For example, 173 cm and 173 inches are different heights; the latter must not be used because a former metric value remained in the field.

No actual body weight is required. Consequently, the form cannot compare your weight with a prescription, determine a body-fat percentage or decide whether weight loss is appropriate. A displayed spread is simply the smallest and largest formula outputs for the same input.

The Four Ideal Body Weight Formulas

Let d = height in inches − 60. The published equations are reproduced below; Hamwi uses pounds, while the other three use kilograms. Table 3

Worked example: female equation at exactly 5 feet 8 inches, or 172.72 cm. Here d = 8:

• Devine: 45.5 + 18.4 = 63.9 kg, about 141 lb.
• Robinson: 49 + 13.6 = 62.6 kg, about 138 lb.
• Miller: 53.1 + 10.88 = 63.98 kg, displayed as 64.0 kg, about 141 lb.
• Hamwi: 100 + 40 = 140 lb, or 63.5029318 kg, displayed as 63.5 kg.

These are calculated examples, not clinical targets. An input of 173 cm is slightly taller than exactly 68 inches, so it should not be described as the identical worked example. The chart uses the exact 68-inch input and rounded pound outputs.

The original article's approximate Hamwi kilogram constants did not reproduce its pound formula. This comparison evaluates Hamwi in its stated pound unit, then converts using 1 lb = 0.45359237 kg. Rounding a converted coefficient before calculation can introduce a different result.

Understanding Your Results

All four formulas depend on the same entered height and selected sex category. Their different constants explain why they give different numbers. A spread does not become a verified healthy interval merely because several equations are included.

The separate BMI reference is derived from BMI = weight in kg ÷ height in meters squared. CDC's adult healthy-weight category is 18.5 to less than 25, for adults aged 20 and older, and is a screening category considered alongside other factors. CDC categories and scope

Derived BMI-boundary example at 1.70 m: 18.5 × 1.70² = 53.465 kg; 25 × 1.70² = 72.25 kg. The second boundary is excluded. The display rounds these values to one decimal place, so the rounded endpoints must not be used to decide the category of a precise boundary measurement.

BMI boundaries are not the same as a historical formula spread. They also do not measure muscle mass or establish an individual's nutrition goal. Use the adult BMI calculator for the separate ratio calculation; the lean-mass estimate and circumference fat estimate use other assumptions.

Adjusted Ideal Body Weight Calculator

An adjusted body weight is not calculated by this form. The former universal instruction to use a 0.4 correction for medication or protein planning should not be followed from this page. A clinical use needs the specific medication, guideline, population and professional assessment; a historical formula output alone cannot supply them.

For arithmetic illustration only, if a chosen reference is 65 kg and another weight is 100 kg, the difference is 35 kg. Choosing an assumed factor of 0.4 gives 65 + 0.4 × 35 = 79 kg. Choosing 0.3 instead gives 75.5 kg. This example shows dependence on an assumed factor, not evidence that either factor is correct for a patient.

Do not enter a value labeled “ideal” from a calculator into a drug-dose calculation on your own. This page does not provide a treatment dose or a clinical adjusted-weight recommendation. Keep any clinician-supplied weight descriptor and method with the plan that requires it.

When documenting a comparison, retain the original height, unit, sex category, formula and rounding. For example, “Devine output at 68 inches” identifies the calculation; “my prescribed goal” would add a conclusion that this website has not established.

Frequently Asked Questions

How do I calculate my ideal body weight?

The tool calculates the four historical equations above from height and the selected sex category. It does not determine an ideal weight for you personally. At 68 inches using the female Devine equation, 45.5 + 2.3 × 8 gives 63.9 kg. Formula reference

What is the ideal body weight calculation formula?

There are multiple named equations. This page compares four, with their units stated in the formula table. The Hamwi output begins in pounds, so its constants should not be treated as kilograms. The same height can therefore give different calculated outputs without selecting one as the correct personal target.

Is the ideal weight calculator accurate?

Its arithmetic can be checked against the formulas and input units. That is different from showing that any output predicts your healthiest weight. The page offers no individual accuracy interval, frame correction or reassurance based on being within ±10% of a formula.

What's the difference between ideal weight and BMI?

These historical equations produce a weight from height and sex category. BMI is a weight-to-height-squared ratio. CDC identifies adult BMI as a screening measure, not a standalone health assessment. The numerical BMI reference on this page applies only to adults 20 and older. CDC explanation

Sources

1. Peterson, Thomas, Blackburn and Heymsfield: Universal equation for estimating ideal body weight and body weight at any BMI, 2016, Table 3 historical formulas and Introduction height convention. Direct PMC access displayed a browser check; the authority-hosted indexed table and text were read. This research paper is not an endorsement of a personal weight target.
2. CDC: Adult BMI Categories, formula, ages 20 and older, inclusive 18.5 and exclusive 25 boundaries, screening context.

Sources checked October 5, 2026. The article, worked examples, injected chart and result cards describe the same four calculations.