BMI Calculator — Free Bupa-style Alternative
The Bupa BMI calculator is a solid quick-check tool. Ours uses the identical NHS-standard formula and adds reverse BMI, child & teen BMI, pregnancy BMI, and saveable results — all for free, no Bupa membership needed.
Independent BMI tool. Not affiliated with Bupa — we use the identical WHO/NHS standard formula and add features they don't offer.
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What you get here that Bupa doesn't
Same NHS-standard formula. More tools. No sign-up wall.
Same NHS / WHO formula
We use the exact same calculation (weight kg ÷ height m²) and the same healthy-weight band (18.5–24.9) Bupa uses. Results match to one decimal place.
Reverse BMI tool
Set a target BMI and get a target weight in kg, lbs, and stones — Bupa doesn't offer this. Useful for setting evidence-based weight-loss or gain goals.
Child & teen BMI percentiles
Bupa's adult tool doesn't cover children. Our child calculator (ages 2–19) uses CDC age-and-sex percentile bands the way the NHS does.
Pregnancy BMI with IOM ranges
Enter your pre-pregnancy weight and get IOM/NICE-recommended weight-gain ranges for singleton or twin pregnancies.
56+ evidence-based articles
Bupa publishes around a dozen weight-focused articles. We have 56+ peer-reviewed-sourced articles with 400+ FAQs and a full glossary.
No sign-up or membership wall
Everything is free and works without an account. Optional sign-in only if you want to save and track your BMI over time.
Side-by-side comparison
| Feature | BMI Health Checker | Bupa |
|---|---|---|
| NHS / WHO standard formula | ||
| Metric and imperial units | ||
| Stones and pounds (UK) | ||
| Reverse BMI (target weight) | — | |
| Child & teen BMI (CDC percentiles) | — | |
| Pregnancy BMI (IOM/NICE ranges) | — | |
| Body fat percentage tool | — | |
| Calorie / TDEE calculator | — | |
| Ideal weight (4 formulas) | — | |
| NICE ethnicity-adjusted thresholds | Limited | |
| Save BMI history (free account) | — | |
| Email results to yourself | — | |
| Installable PWA (works offline) | — | |
| 400+ FAQs | — | |
| Membership / sign-up required | Optional | Not required for BMI |
| Cost | £0 | £0 |
Comparison based on publicly available information at time of publication. Features may change.
Bupa BMI — Common Questions
Quick answers to the most common questions
Both calculators use the same WHO/NHS-standard formula (weight in kilograms divided by height in metres squared) and the same healthy-weight range (BMI 18.5–24.9). Numerical results will match to one decimal place. Our tool adds features Bupa doesn't offer — reverse BMI, child BMI, pregnancy BMI, and saveable results — and we're entirely free with no membership wall.
No — the Bupa BMI calculator is free to use without a membership. The same applies here: our BMI tool is completely free, with no signup needed. An optional free account lets you save your BMI history if you want to track changes over time.
Bupa uses the standard WHO/NHS healthy-weight range of 18.5 to 24.9. Below 18.5 is underweight, 25 to 29.9 is overweight, and 30 or above is obese. We use these exact same ranges.
Bupa, like the NHS and NICE, recommends lower BMI thresholds for South Asian, Chinese, other Asian, Middle Eastern, Black African, and African-Caribbean adults — overweight starts at BMI 23 and obese at BMI 27.5. Our calculator includes these NICE thresholds and explains them in plain English.
If you only need a one-off BMI check, both tools give the same result. Choose ours if you want: a reverse BMI tool to find your target weight, a child or pregnancy BMI version, results in stones and pounds, an installable mobile app version, or to save and track your BMI over time without an insurance membership.
No — we're an independent UK health-tools site. We're not affiliated with, endorsed by, or partnered with Bupa. We use the same NHS-standard BMI formula because it's the universally accepted clinical standard.
Bupa Health Centres include a BMI measurement as part of a Bupa Health Assessment, which is a paid service. The NHS also offers free BMI checks at your GP surgery. This online tool gives you the same calculation instantly and for free, without an appointment.
On the Bupa website, navigate to their health information section and find the BMI calculator. Enter your height and weight in metric or imperial. The same data here gives the same result — instantly, with extra context and tools.
Have another question? Browse our full article library or try a free calculator.