“What should I weigh for my height?” The cleanest starting answer is a range, not a number: the band where body mass index sits in the healthy zone. It is a simple, defensible upper and lower bound — and worth pairing with a reality check.
The Rule That Produces the Range
BMI is weight divided by height squared. The healthy adult band is a BMI between 18.5 and 24.9. Flip that rule around and the healthy weight range falls out directly.
Healthy low = 18.5 × height² · Healthy high = 24.9 × height² (height in meters)
Worked for a Few Common Heights
| Height | Meters | Height² | Healthy range (kg) | Healthy range (lb) |
|---|---|---|---|---|
| 5'5" | 1.65 | 2.72 | 50–68 | 111–149 |
| 5'7" | 1.70 | 2.89 | 53–72 | 118–159 |
| 5'10" | 1.78 | 3.17 | 59–79 | 129–174 |
| 6'1" | 1.85 | 3.42 | 63–85 | 139–188 |
| 6'4" | 1.93 | 3.72 | 69–93 | 152–205 |
Take 5'7" (1.70 m): 18.5 × 2.89 ≈ 53 kg and 24.9 × 2.89 ≈ 72 kg. That is your honest band — about 53–72 kg, roughly 118–159 lb.
How to Read BMI Categories
- Under 18.5 — underweight. Worth discussing, especially if energy or appetite suffer.
- 18.5–24.9 — the healthy/normal band.
- 25–29.9 — overweight. A flag to consider, not a sentence.
- 30 and above — obesity. A signal that medical guidance is worthwhile.
The Honest Limits of BMI
BMI is height-and-weight arithmetic with a blind spot: it cannot tell muscle from fat. A professional athlete at 6'3" can carry a BMI of 28 while being very lean, simply because muscle is dense. For people who are highly muscular, a waist circumference or body-fat measurement tells a truer story. And for children, BMIs are compared against age- and sex-specific percentile charts, not the adult band. Use the range as your compass, and let a clinician be the final guide.
See your exact band without the spreadsheet. Enter your height and weight into the HeightFast converter and the healthy range plus your current BMI appear instantly.