Healthy Weight Calculator
Find your healthy weight range based on BMI guidelines and the Robinson ideal weight formula.
Find your healthy weight range based on standard BMI guidelines (18.5–24.9) and see how it compares to the Robinson formula's single-point ideal weight estimate.
How Healthy Weight Calculator Works
The healthy weight range is calculated by rearranging the BMI formula: minimum healthy weight = 18.5 × height(m)², and maximum healthy weight = 24.9 × height(m)² — the same BMI thresholds used by the World Health Organization to define the "normal weight" category, just solved for weight instead of BMI.
The Robinson (1983) formula provides a single-point estimate rather than a range: 52 kg + 1.9 kg per inch over 5 feet for men, or 49 kg + 1.7 kg per inch over 5 feet for women — and is floored at the minimum healthy weight so it never suggests a target below the healthy BMI range.
If you enter your current weight, the calculator also shows your current BMI, places you on a visual scale from underweight to obese, and compares your weight directly against the Robinson ideal to show how far above or below that single-point target you currently sit.
See It In Action
Who Uses Healthy Weight Calculator and Why
- Finding the full healthy weight range for your height rather than a single target number.
- Comparing where your current weight falls within that range against the single-point Robinson formula estimate.
- Getting a starting reference before setting a weight goal, alongside a visual scale of where you currently sit.
Mistakes to Avoid
- Treating the Robinson ideal weight as the one correct target rather than one single-point estimate — the wider BMI-based healthy range is generally the more practical goal.
- Not accounting for the note this calculator provides for adults 65 and older, where a somewhat higher BMI may be more appropriate than the standard adult range.
- Assuming being above the Robinson figure but still inside the healthy BMI range means something is wrong — it's normal and expected for the two figures to disagree.
Tips for Best Results
- Aim to land anywhere within the healthy weight range rather than at one specific number — the range accounts for natural variation in build far better than a single-point formula does.
- If you're a similar weight to the Robinson estimate but well inside the healthy BMI range, there's no need to specifically chase the lower number.
Fixing Common Problems
My current weight is inside the healthy range but well above the Robinson estimate. — This is expected and not a cause for concern — Robinson gives a single historical point estimate, while the BMI-based range reflects a broader, more realistic healthy zone for your height.
Terms Explained
Healthy weight range: The span of weights corresponding to a BMI between 18.5 and 24.9 for a given height, calculated by solving the BMI formula for weight instead of BMI.