Body mass index · in your browser

Online BMI Calculator Two numbers. One verdict-free answer.

Most BMI calculators on the internet want your email before they hand back a number. They route height and weight through a server, log them next to an IP, and dress the result up with a sales funnel for diet pills. Morph runs the math locally — type the numbers, read the number, close the tab. No account, no upload, no health data leaving your device. free on your device a month for the rest of Morph; the first ten thousand subscribers are grandfathered forever.

Open BMI Calculator
01
CALCULATE

The math, run in your browser tab.

Weight divided by height squared. Metric or imperial. The formula is one line of JavaScript and it runs locally — no fetch, no submit button leading to a server endpoint, no logged input.

Open the tool
Runs on your device · free · no account

What it actually does

02
CATEGORIZE

WHO buckets, no commentary

Underweight, normal, overweight, obese I/II/III. The category appears next to the number. We do not interpret it for you.

03
PRIVACY

Health data stays here

Reload the tab and the inputs are gone. Nothing was logged.

04
NO FUNNEL

No email gate, no upsell

Type, read, close. The number is the product.

How it works

  1. Open morph.cool/bmi-calculator in any modern browser. No account, no install.
  2. Toggle metric or imperial — kilograms and centimeters, or pounds and inches.
  3. Type your height and weight. The result appears as you type.
  4. Read the BMI number plus the WHO bucket. Close the tab when you're done.
  5. Need more than a calculator? The rest of Morph runs on your device too — free, with credits only for AI and server work.
0Upload
∞Email gates
2 inputsHeight + weight

Why people leave the email-gate calculators

The pattern is unmissable. You search "BMI calculator," click the top result, and before the answer surfaces there is a newsletter modal, a cookie consent dance, an ad row, and a sidebar of weight-loss product placements. Your height and weight — small details about your body — get logged next to an IP address and a session token. Morph collapses all of that into the math itself. Two inputs, a number, a category. Nothing gets sent anywhere.

Frequently asked

Where do my height and weight go?

Nowhere. The calculation runs in JavaScript inside your browser tab. No fetch, no submit, no analytics on the input fields. Reload the page and the values are gone.

Metric or imperial?

Both. One toggle. Kilograms and centimeters, or pounds and inches. The math is the same, the units do not matter to your body.

What about the categories?

WHO standard buckets — underweight, normal, overweight, obese class I/II/III. We display the bucket. We do not interpret it for you. Talk to a doctor for that part.

Is BMI even a useful number?

It is one number. It does not know your muscle mass, bone density, age, or fitness level. Treat it as one signal, not a verdict. The tool gives you the math; the interpretation is yours.

Does it work on phone?

Yes. Two inputs and a button. Mobile is the primary form factor for this kind of quick check.

Why is this on Morph?

Morph is the universal utility platform — file conversion, image editor, video editor, screen recorder, plus 300+ small utilities like this one. The calculator is free; Morph Pro.

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