Reverse BMI Calculator
A normal BMI calculator takes your weight and gives you a number. This one takes the number and gives you a weight.
BMI is weight ÷ height², so running it backwards means weight = target BMI × height². At 5'10" a BMI of 22 is 153 lb (69.6 kg) and a BMI of 25 is 174 lb (79.0 kg); at 1.70 m those same two targets are 140 lb and 159 lb. The answer is always height-specific — which is why a single "ideal weight" for everyone cannot exist. The same formula also runs sideways: to find the height that turns a given weight into a target BMI, it is height = √(weight ÷ target BMI).
Reverse BMI Calculator
Common targets
Asian cut-points
WHO international overweight line
Uses the same identity as every other calculator on this site — BMI = kg ÷ m², rearranged. All weights are computed from the standard's own cut-points; none are transcribed. For planning only, not clinical advice.
"Reverse" means two different questions
Searches for a reverse BMI calculator split into two intents, and most tools quietly answer only the first one. Both come from the same identity — you just solve for a different unknown.
solve for weight → weight (kg) = BMI × height (m)²
solve for height → height (m) = √( weight (kg) ÷ BMI )
- "What should I weigh to reach BMI X?" — the common case. Enter your height and a target, get a weight. This is the direction used to turn a clinical instruction ("get your BMI under 25") into a number on a scale.
- "What height would make this weight BMI X?" — the literal reverse, and the one most calculators skip. Useful for understanding proportions, and for checking a BMI that was reported to you without context.
Neither direction changes the person — they only change which term of the formula is the unknown. The arithmetic itself is on the BMI formula page.
Which target BMI is worth aiming at?
This is the part the calculator cannot decide for you, and it is the part most pages get wrong. There is no single "ideal BMI" — the target depends on the standard you are being measured against, and those standards genuinely disagree.
The largest evidence base behind a target comes from a pooled analysis of 239 prospective studies across four continents, restricted to never-smokers and excluding pre-existing disease. It found all-cause mortality was lowest across a band of BMI 20.0–25.0 — not at a single point — with risk rising measurably both below 20 and above 25. If you want one number, the middle of that band (around 22) is the defensible choice, but treat it as the centre of a range rather than a bullseye.
For anyone of Asian descent there is a second consideration that pulls in the opposite direction: the Asian cut-points place the overweight line at 23.0, inside the band that the mortality data would call optimal. The two evidence bases are not measuring the same thing — one is all-cause mortality in mixed populations, the other is early diabetes and cardiovascular risk in Asian populations — which is why this site shows both and lets you pick the one that matches your clinician.
See all eleven standards side by side on the Asian BMI calculator and the BMI chart.
The same target weight is not the same verdict
Here is the trap a reverse BMI calculator hides. Ask "how much can I weigh?" and the answer depends entirely on which standard is judging you. At a fixed height of 1.70 m (5'7"), these are the weights at which each standard crosses into obese:
| Obesity line | Standards that set it there | Weight at 1.70 m | Weight at 5'7" |
|---|---|---|---|
| BMI 25 | WHO Asia-Pacific · Hong Kong · Japan · South Korea · India / South Asia | 72.3 kg | 159 lb |
| BMI 27.5 | WHO Asian action points · Singapore · NICE (Asian groups) · ADA 2026 (Asian) | 79.5 kg | 175 lb |
| BMI 28 | China | 80.9 kg | 178 lb |
| BMI 30 | WHO international | 86.7 kg | 191 lb |
At one height, one person crosses into "obese" anywhere between 72.3 kg and 86.7 kg — a spread of 14.5 kg depending purely on the document being applied. Nothing about the person changes across those rows; only the line does. This is why a reverse BMI answer is only meaningful alongside the standard it was computed against.
The rows are generated from each authority's own published cut-point, not typed by hand. Every standard is documented on the Asian BMI chart by country and the obesity classes page.
The weight at every BMI, from 4'10" to 6'4"
A reference table for the six values people actually search for — the bottom and top of the healthy band, the mortality-minimum midpoint, the WHO overweight and obesity lines, and the Asian cut-points. Every cell is target BMI × height², rounded to the nearest pound or kilogram, so this table and the calculator above can never disagree.
Imperial — weight in pounds
| Height | BMI 18.5 | BMI 22 | BMI 23 | BMI 25 | BMI 27.5 | BMI 30 |
|---|---|---|---|---|---|---|
| 4'10" | 89 lb | 105 lb | 110 lb | 120 lb | 132 lb | 144 lb |
| 4'11" | 92 lb | 109 lb | 114 lb | 124 lb | 136 lb | 149 lb |
| 5'0" | 95 lb | 113 lb | 118 lb | 128 lb | 141 lb | 154 lb |
| 5'1" | 98 lb | 116 lb | 122 lb | 132 lb | 146 lb | 159 lb |
| 5'2" | 101 lb | 120 lb | 126 lb | 137 lb | 150 lb | 164 lb |
| 5'3" | 104 lb | 124 lb | 130 lb | 141 lb | 155 lb | 169 lb |
| 5'4" | 108 lb | 128 lb | 134 lb | 146 lb | 160 lb | 175 lb |
| 5'5" | 111 lb | 132 lb | 138 lb | 150 lb | 165 lb | 180 lb |
| 5'6" | 115 lb | 136 lb | 143 lb | 155 lb | 170 lb | 186 lb |
| 5'7" | 118 lb | 140 lb | 147 lb | 160 lb | 176 lb | 192 lb |
| 5'8" | 122 lb | 145 lb | 151 lb | 164 lb | 181 lb | 197 lb |
| 5'9" | 125 lb | 149 lb | 156 lb | 169 lb | 186 lb | 203 lb |
| 5'10" | 129 lb | 153 lb | 160 lb | 174 lb | 192 lb | 209 lb |
| 5'11" | 133 lb | 158 lb | 165 lb | 179 lb | 197 lb | 215 lb |
| 6'0" | 136 lb | 162 lb | 170 lb | 184 lb | 203 lb | 221 lb |
| 6'1" | 140 lb | 167 lb | 174 lb | 189 lb | 208 lb | 227 lb |
| 6'2" | 144 lb | 171 lb | 179 lb | 195 lb | 214 lb | 234 lb |
| 6'3" | 148 lb | 176 lb | 184 lb | 200 lb | 220 lb | 240 lb |
| 6'4" | 152 lb | 181 lb | 189 lb | 205 lb | 226 lb | 246 lb |
Columns 18.5 and 25 bracket the WHO healthy band; 22 is its mortality-minimum midpoint; 30 is the WHO obesity line. The 23 and 27.5 columns are the Asian overweight and obesity lines.
Metric — weight in kilograms
| Height | BMI 18.5 | BMI 22 | BMI 23 | BMI 25 | BMI 27.5 | BMI 30 |
|---|---|---|---|---|---|---|
| 145 cm | 39 kg | 46 kg | 48 kg | 53 kg | 58 kg | 63 kg |
| 150 cm | 42 kg | 50 kg | 52 kg | 56 kg | 62 kg | 68 kg |
| 155 cm | 44 kg | 53 kg | 55 kg | 60 kg | 66 kg | 72 kg |
| 160 cm | 47 kg | 56 kg | 59 kg | 64 kg | 70 kg | 77 kg |
| 165 cm | 50 kg | 60 kg | 63 kg | 68 kg | 75 kg | 82 kg |
| 170 cm | 53 kg | 64 kg | 66 kg | 72 kg | 79 kg | 87 kg |
| 175 cm | 57 kg | 67 kg | 70 kg | 77 kg | 84 kg | 92 kg |
| 180 cm | 60 kg | 71 kg | 75 kg | 81 kg | 89 kg | 97 kg |
| 185 cm | 63 kg | 75 kg | 79 kg | 86 kg | 94 kg | 103 kg |
| 190 cm | 67 kg | 79 kg | 83 kg | 90 kg | 99 kg | 108 kg |
| 195 cm | 70 kg | 84 kg | 87 kg | 95 kg | 105 kg | 114 kg |
| 200 cm | 74 kg | 88 kg | 92 kg | 100 kg | 110 kg | 120 kg |
Read a row and the height-dependence is obvious: at 5'0" a BMI of 25 is 128 lb, at 6'0" it is 184 lb. Any page quoting one target weight for all heights has dropped the height term from the formula.
Every standard plotted on one axis
The same eleven cut-points drawn to scale across a 15–35 axis. The gap that matters for a reverse-BMI target is the distance between the obesity lines.
Dashed lines mark 23 and 25 — the two numbers this whole topic turns on. Green is the normal range, amber underweight, orange overweight / raised risk, red obesity / high risk.
Three things a target weight cannot tell you
A reverse BMI result is exact arithmetic about weight and height. It says nothing about composition, which is where the number gets misused:
- It cannot tell muscle from fat. BMI cannot separate the two, so a weight that reads BMI 25 may be lean on someone who lifts and overweight on someone who does not. If you train with weights regularly, a target slightly above 25 can be entirely reasonable — the number is a screen, not a sentence.
- It cannot tell you where the fat sits. Central fat carries risk that total weight does not capture. A BMI of 22 with a waist over 90 cm (men) or 80 cm (women) is a raised-risk combination that the arithmetic above cannot see. That is what the waist-to-height ratio calculator is for — one threshold, keep your waist under half your height, no ethnicity switch required.
- It does not apply to children or during pregnancy. Adult BMI cut-points are invalid for under-18s, who are assessed against age- and sex-specific percentile curves, and for pregnancy, which uses gestational weight-gain ranges derived from pre-pregnancy BMI. Hitting a target weight is not the goal in either case.
If your target comes from a clinician, the clinically useful move is to ask which standard the number is based on — because as the table above shows, the answer changes by more than a stone depending on the document. And if you want a single measurement that needs no standard at all, measure your waist.
Frequently asked questions
- What is a reverse BMI calculator?
- A reverse BMI calculator runs the usual formula backwards. A standard BMI calculator takes your weight and height and returns a BMI number; a reverse calculator takes a target BMI and your height and returns the exact weight that would produce it. Because BMI is weight divided by height squared, the reverse form is weight = target BMI × height². Some tools, including this one, also solve the other way — the height at which a given weight produces the target BMI — which is height = √(weight ÷ target BMI).
- How do you reverse the BMI formula?
- Take BMI = kg ÷ m² and rearrange it. To solve for weight, multiply the target BMI by your height in metres squared: at 1.70 m, a target of 22 gives 22 × 1.70² = 63.6 kg (140 lb). To solve for height, divide your weight by the target BMI and take the square root: 70 kg at BMI 25 gives √(70 ÷ 25) = 1.673 m, or about 167 cm. In imperial units the weight form is BMI × height (in)² ÷ 703.
- What weight is BMI 25 for my height?
- It depends entirely on your height, because the height term is squared. BMI 25 is 128 lb at 5'0", 160 lb at 5'6", 174 lb at 5'10" and 184 lb at 6'0" — or in metric, 64 kg at 160 cm, 72 kg at 170 cm and 81 kg at 180 cm. Any chart that quotes a single target weight regardless of height has left the height term out of the calculation.
- Why does the same target BMI give a different weight for someone of the same height on a different standard?
- The target BMI number is the same; what changes is which number you should be targeting. The WHO international scale puts the overweight line at 25.0 and obesity at 30.0, while the Asian cut-points put overweight at 23.0 and obesity at 25.0 — so a target weight derived from 'stay under the obesity line' differs by more than a stone depending on which document applies to you. At 1.70 m the obesity line falls between 72.3 kg and 86.7 kg across the eleven standards this site documents.
- Does a reverse BMI calculator work during pregnancy or for children?
- No. Adult BMI cut-points and any weight derived from them are not valid under 18 or during pregnancy. Children and adolescents are assessed against age- and sex-specific percentile curves, and pregnancy uses gestational weight-gain ranges based on pre-pregnancy BMI. A target weight from an adult calculator should not be applied to either group.
- Is the target weight from a reverse BMI calculator accurate if I lift weights?
- It is exactly accurate as arithmetic and unreliable as a body-composition goal. BMI cannot distinguish muscle from fat, so the weight that produces BMI 25 on a lean, muscular person can be a healthy physique while the same weight on someone with more body fat is not. If you train with weights, treat the result as a range and check your waist measurement as well.
Data sources and how we verify them
Every cut-point, band and formula on this page is taken from the issuing authority's own document, listed below. We do not use second-hand summaries, and we do not fill gaps with numbers no source states.
- World Health Organization (WHO)
International cut-points (25 / 30) and the 2004 Asian action points
- National Health Commission of the PRC
China's current adult cut-points — WS/T 428 (24 / 28) and waist criteria
- Department of Health, Hong Kong, China
Hong Kong classification (23 / 25), from the Population Health Survey 2020-22
- Health Promotion Board, Singapore
Singapore's three-band risk ladder (18.5–22.9 / 23.0–27.4 / ≥27.5)
- Japan Society for the Study of Obesity (JASSO)
Japan's classification, which has no overweight tier (obesity from 25)
- Korean Society for the Study of Obesity (KSSO)
Korea's classification and abdominal-obesity waist thresholds
- Indian Council of Medical Research / Misra consensus
South Asian cut-points, including the 18.0 lower bound
- National Institute for Health and Care Excellence (NICE), UK
Lower ethnic-specific thresholds for Asian adults in the UK (23 / 27.5)
- American Diabetes Association (ADA)
2026 standards — Asian obesity at 27.5 and central obesity overriding BMI
Cut-points are population-level statistical thresholds, not individual diagnoses. If your value sits near a category line, measure your waist as well and read it alongside body-fat percentage. Last checked: 2026-09-15.
Sources
- Global BMI Mortality Collaboration — Body-mass index and all-cause mortality: individual-participant-data meta-analysis of 239 prospective studies in four continents (Lancet 2016; PMID 27423262; all-cause mortality minimal at BMI 20.0–25.0)
- WHO — Obesity and overweight fact sheet
- WHO Expert Consultation — Appropriate body-mass index for Asian populations (Lancet 2004;363:157–163; overweight action point 23.0, high-risk action point 27.5)
- WHO / IASO / IOTF — The Asia-Pacific Perspective: Redefining Obesity and Its Treatment (2000; overweight from 23.0, obesity from 25.0)
- ADA Standards of Care in Diabetes 2026 — adult overweight and obesity: Asian populations obese from BMI 27.5, central obesity overrides BMI within 23.0–27.4
- NICE guideline NG246 — BMI thresholds for South Asian, Chinese, other Asian, Middle Eastern and Black African/Caribbean adults (overweight from 23.0, obesity from 27.5)
Every figure above was checked against the original document. This page is general information, not medical advice.
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Content on this site is for general information only and does not constitute medical advice. Consult a doctor or qualified health professional for personal health concerns. Last updated: August 9, 2026.
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