Just under the overweight cut
- BMI
- 24.9
- Band
- normal
At 175 cm, 76.4 kg lands just under 25. The screening label is still normal weight; one more kilogram usually is not.
Health & Fitness
BMI Calculator — Body Mass Index
Free BMI calculator. Enter your weight and height to get your Body Mass Index and health category instantly.
Formula and sources updated · Data sources · 3View algorithm, constants and default inputs (JSON)
About this calculator
BMI is weight in kilograms divided by height in metres squared. This page gives the adult screening measure for ages 20 and older; children and teens need age- and sex-specific BMI-for-age interpretation. BMI does not directly measure body fat and is not a diagnosis.
Recomputed from this page's implementation at build time · checked 2026-10-27
The same four adult bands, and why 24.9 and 25.0 are different answers
BMI is one ratio with four adult labels. The interesting part is not the arithmetic — it is where the cut-points sit, what they refuse to say about muscle or children, and how a tenth of a point can change the screening label.
- 22.9 70 kg at 175 cm adult screening BMI
- 29.4 Same height, 90 kg crosses into overweight
- 27.3 Same weight, 160 cm height moves BMI faster than people expect
Cut-points that change the sentence
The cut-point itself
- BMI
- 25.0
- Band
- overweight
CDC adult categories put 25.0 in overweight. The page uses the same open/closed edges as the scale chart: below 25 is normal, 25 and above is overweight.
Obesity starts at 30, not 'around 30'
- BMI
- 30.0
92 kg at 175 cm crosses 30. The obese band is a hard threshold on this page, not a soft clinical impression.
Inputs that produce no BMI
-
You typed
- weight
- 70
- height
- 0
It answeredinputErrorZero height is refused
Height enters as a squared denominator. Zero centimetres would send the ratio to infinity; the page returns an input error instead of printing Infinity.
-
You typed
- weight
- -10
- height
- 170
It answeredinputErrorNegative weight is refused
A negative mass is not a screening input. The page rejects non-positive weight and height rather than inventing a negative BMI band.
-
You typed
- weight
- 0
- height
- 170
It answeredinputErrorZero weight is refused
Zero kilograms is not an adult screening case. The calculator asks for a positive weight.
What this page deliberately does not claim
- Adult cut-points only
- The four bands match adult screening used by CDC and WHO for ages 20 and older. Children and teens need BMI-for-age percentiles that this page does not compute.
- Not a fat measurement
- BMI ignores muscle, bone and fat distribution. Two adults with the same BMI can have very different body composition; the sentence under the result is a screening label, not a diagnosis.
- Kilograms and centimetres only
- Inputs are kg and cm. Height is divided by 100 before squaring. Imperial unit pages elsewhere on the site handle lb/in conversions; this tool stays on one unit pair so the formula stays auditable.
Against a clinical BMI page
-
CDC Adult BMI Calculatorchecked 2026-10-27
- Theirs
- Official adult categories with clinical framing and separate child tools.
- Here
- The same adult cut-points, an on-page scale chart, and an explicit sentence naming the band for the current inputs.
Why they built it that wayCDC publishes both the adult calculator and the category table this page cites.
Matching the public cut-points matters more than inventing a fifth band. Divergence here would be a correctness bug, not a product feature.
Enter 70 kg and 175 cm: BMI reads 22.9 and the band says normal weight. Change weight to 92 kg: BMI crosses 30 and the band switches to obese.
Cross-checked adult cut-points against CDC adult BMI categories and WHO GHO BMI topic pages dated in the sources list · impl 40d27cfe
Method and assumptions
Convert height from centimetres to metres, square it, then divide weight in kilograms by that value. 70 kg / (175 cm / 100)² ≈ 22.86 kg/m².
Data sources
Disclaimer
These calculators are for general information only and are not a medical device, a diagnosis or a treatment plan. Reference ranges describe populations, not individuals, and do not account for pregnancy, medication, disability or athletic training. Discuss your own situation with a qualified healthcare professional.
Implementation source
This record describes the implementation used by this page. It is not independent validation. External references, when available, support only the stated formula or definition; estimates and custom rules retain their own assumptions.
Frequently asked questions
How do you calculate BMI?
BMI equals weight in kilograms divided by height in metres squared. This calculator accepts kilograms and centimetres, converting height to metres before calculating.
What do BMI values like 24, 25, 27, and 30 mean?
For adults aged 20 and older, the healthy-weight BMI range is 18.5 to under 25. A BMI of 24 is in that range; 25 and 27 fall in the overweight range (25 to under 30), and 30 starts the obesity category. These screening categories apply regardless of sex, do not measure body fat directly, and are not a diagnosis.
Does BMI mean the same thing for children?
No, and the categories do not transfer at all. Children and teenagers are assessed against age- and sex-specific percentile charts, because body composition changes rapidly with growth. A number that is unremarkable in an adult can be a concern in a nine-year-old. Never read an adult band against a child.
Why does a small height error change the result so much?
Because height is squared in the formula. At around 1.7 metres, a two centimetre error moves the result by roughly two and a half percent — enough to cross a category boundary near a cut-off. That is why the same person can get different BMI readings on different days and on different machines.