Calculate your Body Mass Index (BMI) — a WHO-standard screening from height and weight — in metric (kg/cm) or imperial (lb/ft·in). This BMI calculator gives your BMI, WHO category (Underweight through Obese Class I, II, III), healthy weight range for your height, weight to gain or lose to reach normal, plus BMI Prime and Ponderal Index. Fast, private, no signup.
Quick answer: BMI = kg ÷ m² or (lb ÷ in²) × 703. Healthy is 18.5–24.9. See Formula, BMI Chart and healthy weight by height — or jump to Calorie Calculator and TDEE Calculator.
Enter height & weight and tap Calculate BMI. Results include WHO category, visual scale, healthy range, target-weight delta, BMI Prime and Ponderal Index. How to use →
WHO Standard • Metric & Imperial • Instant Results
Example: 165, 175, 180 cm
Example: 60, 70, 85 kg
Formula: BMI = kg / m² or 703 × lb / in². Press Enter to calculate. No data is stored.
Enter height & weight, then tap Calculate
Get your BMI, WHO category (Underweight → Obese III), healthy weight range & weight needed to reach normal.
Tip: 175 cm ≈ 5′9″, 70 kg ≈ 154 lb. The calculator rounds BMI to one decimal — same as CDC and NHS.
Body Mass Index is a simple, fast screening number that compares weight to height. For adults 20+ it groups weight into Underweight, Healthy Weight, Overweight and Obese (Classes I-III) and flags higher average risk for chronic conditions such as type 2 diabetes, hypertension and cardiovascular disease. The WHO and CDC use the same adult bands (18.5, 25, 30) worldwide — this calculator matches them exactly.
Think of BMI as a low-cost first filter. A BMI of 18.5–24.9 puts you in the healthy mean-risk zone; above or below, context matters. Pair it with TDEE for calorie needs.
One formula, two unit systems. The calculator converts to kg/m² internally, so either path is identical:
Metric
BMI = weight (kg) ÷ height² (m²)
Height in meters = cm ÷ 100. Example: 1.75 m → m² = 3.0625
Imperial
BMI = 703 × weight (lb) ÷ height² (in²)
Height in total inches = ft×12 + in. 703 reconciles units to kg/m².
Healthy weight (kg) = BMI × height² (m²)
Plug 18.5 and 24.9 to get your healthy range — the calculator does this automatically. See Reverse BMI and lookup table.
Adults 20+ share one global scale. The four headline bands split obesity into three clinical classes so a BMI of 31 reads differently from 42.
| Category | BMI Range | Health Risk | What it signals |
|---|---|---|---|
| Underweight | < 18.5 | Increased — nutrition, bone | May need nutritional assessment |
| Healthy Weight | 18.5 – 24.9 | Low / Average | Typical low-risk reference band |
| Overweight | 25.0 – 29.9 | Increased | Flag to review waist, activity, diet |
| Obese Class I | 30.0 – 34.9 | High | Clinically obese — follow-up advised |
| Obese Class II | 35.0 – 39.9 | Very high | Higher cardiometabolic risk |
| Obese Class III (Severe) | ≥ 40.0 | Very high | Severe — medical guidance recommended |
Cutoffs per WHO global consultation and CDC Adult BMI Categories.
Find your height and read the weight that keeps BMI in the healthy band. The calculator above gives your exact personalized range; this table is a quick reference.
| Height | Healthy weight (lb) | Healthy weight (kg) | Midpoint ~ BMI 22 (kg) |
|---|---|---|---|
| 4′10″ (147 cm) | 88–119 | 39.9–53.8 | 47.5 |
| 4′11″ (150 cm) | 92–123 | 41.5–55.7 | 49.5 |
| 5′0″ (152 cm) | 95–128 | 43.1–58.0 | 50.8 |
| 5′1″ (155 cm) | 98–132 | 44.4–60.0 | 52.8 |
| 5′2″ (157 cm) | 101–136 | 46.0–61.6 | 54.2 |
| 5′3″ (160 cm) | 104–141 | 47.4–64.0 | 56.3 |
| 5′4″ (163 cm) | 108–145 | 49.0–65.9 | 58.4 |
| 5′5″ (165 cm) | 111–150 | 50.4–68.0 | 59.9 |
| 5′6″ (168 cm) | 115–154 | 52.2–70.0 | 62.1 |
| 5′7″ (170 cm) | 118–159 | 53.5–72.3 | 63.6 |
| 5′8″ (173 cm) | 122–164 | 55.3–74.5 | 65.8 |
| 5′9″ (175 cm) | 125–169 | 56.7–76.6 | 67.4 |
| 5′10″ (178 cm) | 129–174 | 58.6–78.9 | 69.7 |
| 5′11″ (180 cm) | 133–179 | 60.0–81.0 | 71.3 |
| 6′0″ (183 cm) | 136–184 | 61.9–83.5 | 73.7 |
| 6′1″ (185 cm) | 140–189 | 63.5–86.0 | 75.3 |
| 6′2″ (188 cm) | 144–194 | 65.3–88.0 | 77.8 |
| 6′3″ (191 cm) | 148–199 | 67.1–90.4 | 80.3 |
| 6′4″ (193 cm) | 152–205 | 68.9–93.0 | 81.9 |
Computed as 18.5×m² (low) and 24.9×m² (high). Pounds = kg ÷ 0.453592. Midpoint at BMI 22.
The same BMI formula is used globally, but diabetes and cardiovascular risk rises at lower BMI in many East, Southeast and South Asian populations. Both a 2004 WHO expert consultation and ADA (screening at BMI ≥23 for Asian Americans) recommend lower action points.
| Category | Standard WHO | Asian guidance | Notes |
|---|---|---|---|
| Healthy weight | 18.5 – 24.9 | 18.5 – 22.9 | Upper normal 22.9 |
| Overweight | 25.0 – 29.9 | 23.0 – 27.4 | ADA screens at ≥23 |
| Obese | 30.0+ | 27.5+ | WHO Asian trigger 27.5 |
WHO Lancet 2004 and ADA Standards of Care — “At BMI ≥23 kg/m², diabetes screening is recommended for Asian Americans”.
18.5×m² – 24.9×m² is the weight window that keeps BMI in normal. The result panel shows it for your exact height and how many kg/lb to gain or lose to re-enter normal. Midpoint (~BMI 22) is often quoted as a stable target.
Prime = BMI ÷ 25. A Prime of 0.85 = 15% below the upper normal limit; 1.20 = 20% over. Above 1.00 signals overweight; above 1.20 signals Obese I.
kg ÷ m³. Because it divides by height cubed, it correlates better for very tall or short adults and for children's growth charts. Typical adult range ~11–15 kg/m³.
Green = healthy band; yellow/orange = transition zones; reds = obesity classes. The triangle is your BMI on the 10–40 scale. Sharing an edge is a population threshold, not a body-composition verdict.
For planning, pair these numbers with energy intake. See TDEE Calculator and Calorie Calculator.
Two versions of the same person — the math converges to the same BMI after unit conversion.
Same height (175 cm) at 85 kg: BMI = 85 ÷ 3.0625 = 27.8 → Overweight. To reach 24.9 need 76.3 kg → lose 8.7 kg (19.2 lb). At 95 kg: BMI 31.0 → Obese I → lose 18.7 kg to 24.9. The tool reports this delta automatically.
Rearranged: weight = BMI × height². Use any target within the chart — most people target the middle of healthy (~22) or the upper edge (24.9) as an interim goal.
Quick mental method: take the healthy weight table row for your height — it is already 18.5 and 24.9 solved.
BMI's strength is simplicity; its weakness is that it ignores what weight is made of.
BMI labels muscular adults overweight (27–32) despite low fat. Use waist, waist-to-height ≤0.5, body-fat or strength markers alongside BMI.
Muscle loss with aging means similar BMI = more fat. Some guidance permits 23–25 as the lower bound of healthy above 65.
Use BMI-for-age percentile (CDC/WHO growth charts), not adult 18.5/25. 85th–95th = overweight, >95th = obese for age/sex. This page is adult-only.
Do not use BMI during pregnancy. Gestational weight guidance uses pre-pregnancy BMI as one input.
Risk rises at lower BMI for many Asian populations (see table). Frame and fat distribution also diverge at the same BMI.
Waist >102 cm (men) or >88 cm (women) raises cardiometabolic risk even inside healthy BMI.
A healthy BMI is a by-product of sustainable habits, not crash methods. Small, durable changes outperform big, brief ones:
WHO, CDC and peer-reviewed sources behind the thresholds, formula and context on this page.
This page summarizes public-health standards for information only. Individual interpretation should include waist, history, labs and professional advice.
This BMI calculator provides an estimate based on standard formulas for adults and is for educational and informational purposes only.
Results are most appropriate for adults aged 20+ and should not be used for clinical diagnosis. Children 2–19 require BMI-for-age percentiles; pregnancy requires specific gestational guidance.
Individual health risk depends on body composition, fat distribution, muscle mass, genetics, medical history and lifestyle — not BMI alone. Consult a qualified healthcare professional before making medical or weight-management decisions.
A BMI calculator estimates Body Mass Index — a screening number from height and weight that classifies weight relative to height (Underweight, Healthy, Overweight, Obese I-III). It is not a body-fat test; clinicians use it with other measures.
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This BMI calculator is for informational purposes only and does not replace medical advice. Always consult a healthcare professional.
Content Updated At : 30/08/2026 • 2,850 words • Reviewed • WHO/CDC aligned
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