Enter your height and weight to get started
Try an example, or enter your own values above.
How to use the BMI Calculator
- Type in your height in centimeters.
- Type in your weight in kilograms.
- Click Calculate BMI to instantly see your BMI value and health category.
- Use the Copy or Share buttons to save or send your result.
Tip: BMI is a quick screening number, not a full health diagnosis — pair it with other measures like waist circumference for a fuller picture.
Common mistakes to avoid
- Entering height in feet/inches instead of centimeters.
- Entering weight in pounds instead of kilograms.
- Treating BMI as a diagnosis rather than a general screening number.
BMI categories explained
The four standard adult ranges
The World Health Organization defines four standard adult BMI categories, used worldwide as a quick screening reference: Underweight (below 18.5), Normal weight (18.5–24.9), Overweight (25.0–29.9), and Obese (30.0 and above).
When to use this tool
BMI is commonly used by clinics, insurers, and fitness trackers as a fast first-pass screening number before deeper assessment.
✓ Pros
- Works instantly, right in your browser
- Uses the same formula doctors and clinics reference
- No sign-up, no ads blocking the result
✕ Limitations
- Doesn’t account for muscle mass
- Same ranges applied to all adults regardless of age
- Not a medical diagnosis
The BMI formula
The exact calculation used
BMI is calculated the same way for every adult, regardless of age or sex: BMI = weight (kg) ÷ height (m)². Example: a person who is 170cm (1.7m) tall and weighs 65kg has a BMI of 65 ÷ (1.7 × 1.7) = 22.5 — in the Normal weight range.
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Is a healthy BMI different for everyone?
The BMI formula itself is identical for everyone, but what counts as a "healthy" number can vary slightly by age, sex, and muscle mass. Athletes, for example, often show a higher BMI despite low body fat, since muscle weighs more than fat. This is why BMI works best as a starting screening point rather than a final verdict — pairing it with waist circumference or a body composition check gives a fuller picture.
Quick BMI Reference
See at a glance how common height/weight combinations map to a BMI value and category.
| Height / Weight | BMI | Category |
|---|---|---|
160cm, 50kg | 19.5 | Normal |
170cm, 80kg | 27.7 | Overweight |
180cm, 70kg | 21.6 | Normal |
These are illustrative examples — enter your own exact height and weight above for a precise result.
Features
Medically standard formula
Instant results
No data stored
Mobile friendly
How TickmarkTools compares
An honest, feature-by-feature look at browser-based calculator tools.
| Feature | TickmarkTools | Typical free sites | Premium suites |
|---|---|---|---|
| Price | Free | Free / freemium | Free tier + paid plans |
| Sign-up required | No | Often yes | Yes |
| Data leaves your device | Never | Usually | Usually |
| Watermark on export | None | Sometimes | On free tier |
| Mobile friendly | ✓ | Varies | ✓ |
| Works without account | ✓ | Varies | ✗ |
These are general, illustrative observations about common patterns across free online calculator tools as a category — not verified or benchmarked data about any specific named competitor or product. Individual sites vary and may differ from what's shown here.
Why you can trust this tool
No data stored
Your input is never saved or logged.
Secure processing
All processing happens client-side in your browser.
Fast processing
Results render in milliseconds, no waiting.
Mobile friendly
Use this tool from any device.
No sign-up
No account, no email, no watermark.
Works offline*
Once loaded, this tool needs no internet connection.
Accuracy & limitations
This calculator is built for speed and accuracy, but it's worth understanding what it does and doesn't account for:
- Doesn't distinguish muscle from fat. Very muscular people can show a high BMI despite low body fat.
- Not adjusted for age or sex. The same ranges are applied to all adults, though body composition naturally varies.
- Not diagnostic. BMI is a screening tool, not a substitute for a medical assessment — consult a doctor for personalized advice.
BMI Calculator FAQ
Yes, the BMI Calculator is completely free with no sign-up required.
No, calculations happen entirely in your browser and nothing is uploaded or logged.
BMI is a general screening tool and may not account for muscle mass, age, or body composition — consult a doctor for personalized advice.
A BMI between 18.5 and 24.9 is generally considered a normal, healthy range for adults.
The formula is the same, but healthy ranges can vary slightly based on age, muscle mass, and other factors.
No. All calculations run entirely in your browser, and nothing you enter is ever sent to a server or stored.
💡 Quick Help
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