Ideal Weight Calculator
Find a realistic healthy weight for your height. Instead of one arbitrary number, this calculator shows the classic Devine and Robinson formula results alongside the full healthy BMI range — because "ideal" is a range, not a single point.
How to use this calculator
- Select your sex and enter your height in cm.
- Press Calculate to see formula-based ideal weights and the healthy BMI range.
- Treat the BMI range as your target zone; the formula numbers are reference points within it.
- Combine with the body fat calculator for a fuller picture of what your weight is made of.
Formula used
Robinson (1983): Men 52 kg + 1.9 kg/inch over 5 ft; Women 49 kg + 1.7 kg/inch over 5 ft. The healthy range multiplies BMI limits (18.5 and 24.9) by height in meters squared. The Devine formula was originally created for calculating medication doses, and remains the most cited "ideal weight" formula.
Example calculation
A man of 170 cm (66.9 inches, 6.9 inches over 5 ft):
Devine = 50 + 2.3 × 6.9 = 65.9 kg. Robinson = 52 + 1.9 × 6.9 = 65.1 kg. Healthy BMI range = 53.5 – 72.0 kg — both formulas land comfortably inside it.
Is there really an "ideal" weight?
Not as a single number. The classic formulas (Devine, Robinson, Hamwi, Miller) were developed for clinical purposes — drug dosing and quick assessments — and they assume an average frame. Real healthy weights vary with muscle mass, bone structure, age and body fat distribution.
That's why this calculator emphasizes the healthy BMI range: anywhere within it is statistically associated with good health outcomes for most adults. Use the formula values as center-of-range references, and judge progress by how you feel, perform and measure — not by hitting one decimal-point target.
Why use this calculator?
- Set a realistic target zone instead of chasing a single arbitrary number.
- Compare multiple established formulas at once and see how closely they agree.
- Sanity-check weight-loss goals — targets below the healthy range are a red flag, not ambition.
Frequently asked questions
How much should I weigh for my height?
For most adults, a healthy weight is anywhere that puts your BMI between 18.5 and 24.9 — for 170 cm that's roughly 53–72 kg. Where you personally sit best within that range depends on muscle mass and build.
Why do different formulas give different ideal weights?
Each was derived from different populations and purposes decades apart. They typically agree within a few kilograms, which is precisely why a range is more honest than any single formula's output.
Does age change my ideal weight?
The standard BMI range applies to all adults, though some research suggests slightly higher weights (BMI up to ~27) aren't harmful in older adults and may be protective. Muscle preservation matters more with age than the scale number.
Is ideal weight different for athletes?
Yes — formulas assume average muscle mass. A muscular athlete can healthily exceed formula weights and even the BMI range. Body fat percentage is the better metric in that case.