Free weight percentile calculator
See how your weight ranks for an adult in two seconds. Enter your weight in kilograms or pounds, pick your sex, and the calculator returns your weight percentile and the share of US men or women you're heavier than — modelled with a lognormal curve and a full weight percentile chart — updated live, as you type.
On this page16 sections
| Percentile | Weight |
|---|---|
| 5th | 57 kg (126 lb) |
| 25th | 72 kg (159 lb) |
| 50th (median) | 85 kg (187 lb) |
| 75th | 100 kg (220 lb) |
| 90th | 116 kg (255 lb) |
| 95th | 126 kg (278 lb) |
A ranking against US adults, not a health measure. Why BMI is often better
Results are estimates. Consult a professional.
What is a weight percentile?
A weight percentile tells you where your weight ranks among other adults of the same sex. If you are in the 75th percentile, you are heavier than 75% of adults of your sex — and only 25% weigh more than you. The 50th percentile is the median, the exact middle of the population; the 90th means just one in ten adults weighs more. This weight percentile calculator takes your weight and your sex and returns that ranking instantly, against the US adult population.
Percentile is a ranking, not a measurement and not a verdict. Your weight in kilograms or pounds is a fact about you; your percentile depends on who you are compared against — your sex, and the population used as the reference. This tool uses the US adult distribution, split by sex, because men and women weigh quite differently and ranking against a combined population would be misleading. A 90 kg figure is around the 60th percentile for a US man but well into the top quarter for a US woman.
How weight percentile is calculated
Adult weight is right-skewed: most people cluster around a typical figure, but a long tail of heavier people stretches out to one side. Because of that skew, weight is not a symmetric bell curve, so this calculator does not pretend it is. Instead it models weight as a lognormal distribution — meaning the natural logarithm of weight follows a normal curve, even though weight itself does not.
The calculator takes the logarithm of your weight, works out its z-score on the log scale — how many standard deviations it sits above or below the log-median — and feeds that z-score into the standard-normal cumulative distribution function (CDF). The result, as a percent, is your percentile.
Because the model works on log-weight, the median weight always lands at the 50th percentile, but the steps either side are not symmetric in kilograms: it takes more added weight to climb from the 50th to the 90th percentile than it does to fall from the 50th to the 10th. That asymmetry is exactly the right-skew that a plain bell curve would miss.
A worked example using the weight percentile calculator
Marcus weighs 100 kg (about 220 lb) and wants to know how that ranks for a US man. Here is exactly how the calculator scores him.
- Take the log of the weight. The calculator computes ln(100) ≈ 4.605, working on the log scale because weight is right-skewed.
- Find the z-score. Subtract the men's log-median, ln(85) ≈ 4.443, to get 0.162, then divide by σ_log (0.24): 0.162 ÷ 0.24 ≈ z ≈ 0.68. Marcus is about two-thirds of a standard deviation above the log-median.
- Convert the z-score to a percentile. Feeding z ≈ 0.68 into the standard-normal CDF gives about 0.75 — so roughly 75% of US men weigh less than Marcus.
What does my weight percentile actually mean?
Your percentile is the percentage of same-sex adults who weigh less than you. The calculator states the same thing two ways — your percentile, and the "heavier than X%" line — because they are the same number. An 80th percentile means you weigh more than 80 out of every 100 adults of your sex, and 20 weigh more than you.
- 50th percentile — the median weight for your sex. Half weigh less, half weigh more.
- 75th percentile — heavier than three-quarters of your sex; clearly on the heavier side.
- 25th percentile — lighter than three-quarters of your sex; clearly on the lighter side.
- 95th / 5th percentile — the heaviest or lightest few percent of the population.
Why weight is skewed, not a bell curve
Height, within a sex, is almost perfectly symmetric — there are about as many people 10 cm above average as 10 cm below. Weight is different. There is a hard floor (you cannot weigh much less than your frame allows) but no real ceiling, so the distribution is right-skewed: the heavy tail stretches further than the light one, and the mean sits above the median.
That is why this calculator uses a lognormal model rather than a plain normal one. Taking the logarithm of weight pulls in the heavy tail and makes the distribution roughly symmetric, so the normal-curve maths applies to log-weight. The practical effect: the gap between the 50th and 90th percentile is wider, in kilograms, than the gap between the 10th and 50th — which matches what real population data shows.
Average weight for US adults by sex
The calculator scores you against the US adult distribution for your sex. The table below shows the median and average (mean) weight this model uses, in both kilograms and pounds, so you can see the reference figures behind your percentile.
| Sex (US adults) | Median weight | Average (mean) weight |
|---|---|---|
| Men | 85 kg (187 lb) | 87.5 kg (193 lb) |
| Women | 73 kg (161 lb) | 75 kg (165 lb) |
NHANES-style US adult figures. The mean sits above the median for both sexes — the signature of a right-skewed distribution. These are population figures for adults overall, not adjusted for height or age.
Notice the mean is higher than the median in both rows. On a symmetric bell curve they would be equal; the gap here is the right-skew at work. It also means a calculator that compares you with the average weight rather than the median will place you slightly lower — the median (50th percentile) is the fairer middle, and it is what this tool uses.
Weight percentile chart for US adults
Most people want to see the whole range, not just their own number. The chart below runs the model across common weights and reports the percentile for each, by sex. Find the weight nearest yours and read across — the same reference most calculators split across separate male and female pages, on one table.
| Weight | Men's percentile | Women's percentile |
|---|---|---|
| 120 lb (54 kg) | 3rd | 11th |
| 140 lb (64 kg) | 11th | 28th |
| 160 lb (73 kg) | 26th | 49th |
| 180 lb (82 kg) | 43rd | 68th |
| 190 lb (86 kg) | 52nd | 76th |
| 200 lb (91 kg) | 61st | 82nd |
| 220 lb (100 kg) | 75th | 90th |
| 240 lb (109 kg) | 85th | 95th |
| 260 lb (118 kg) | 91st | 98th |
Percentiles computed from the lognormal model (US men: median 85 kg; US women: median 73 kg; σ_log 0.24 each). An approximate model of US adults overall.
What weight reaches each percentile?
You can also read the model the other way: pick a percentile and see the weight that reaches it. This is the table to use if you want to know, say, what you would weigh at the 25th or the 90th percentile for your sex.
| Percentile | Men's weight | Women's weight |
|---|---|---|
| 5th | 126 lb (57 kg) | 108 lb (49 kg) |
| 10th | 138 lb (63 kg) | 118 lb (54 kg) |
| 25th | 159 lb (72 kg) | 137 lb (62 kg) |
| 50th (median) | 187 lb (85 kg) | 161 lb (73 kg) |
| 75th | 220 lb (100 kg) | 189 lb (86 kg) |
| 90th | 255 lb (116 kg) | 219 lb (99 kg) |
| 95th | 278 lb (126 kg) | 239 lb (108 kg) |
| 99th | 327 lb (148 kg) | 281 lb (128 kg) |
Weights are the lognormal model's value at each percentile, rounded (US men: median 85 kg; US women: median 73 kg; σ_log 0.24 each). The widening gaps toward the top are the right-skew.
Why BMI percentile is often more meaningful than weight percentile
A raw weight percentile ignores one obvious thing: height. A 90 kg figure means something very different on a 165 cm frame than on a 195 cm frame, yet both score the same weight percentile. That is why, for any question about whether a weight is healthy, the BMI — weight divided by height squared — is usually the more meaningful number.
- Weight percentile ranks you against other adults of your sex by weight alone — useful for context, but blind to height.
- BMI normalises weight for height, so it compares like with like and underpins the standard underweight / healthy / overweight bands.
- For children, clinicians use BMI-for-age percentiles, not weight percentiles, for exactly this reason.
How accurate is this weight percentile calculator?
For the question it answers — roughly where an adult weight ranks in the US population by sex — the lognormal model is a reasonable approximation, because adult weight really is close to lognormal and the medians used are well established. But several honest limits are worth knowing.
- It is an approximate lognormal model. Real weight data is close to lognormal but not exactly so, so treat the result as an estimate of your ranking — accurate to a few percentile points, looser at the extreme tails.
- It does not adjust for height. Weight percentile compares you with all adults of your sex regardless of height. For a health-aware comparison, use BMI instead.
- It does not adjust for age. The figures are for US adults overall; average weight varies with age, so a single distribution per sex is a simplification.
- It is a US adult model. If you live elsewhere, your true percentile against your own country's population may differ.
- Sex is binary in this model because the published distributions are reported for men and women separately; pick whichever distribution you want to be ranked against.
Data sources and methodology
The population parameters are NHANES-style US adult figures from the CDC's National Health and Nutrition Examination Survey: median weights of about 85 kg (187 lb) for men and 73 kg (161 lb) for women, with a log-scale spread (σ_log 0.24) chosen so the implied means (~87.5 kg men, ~75 kg women) and standard deviations (~18–21 kg) match published adult figures. The percentile is computed by taking the z-score of the log of your weight and applying the standard-normal cumulative distribution function, implemented via the Abramowitz & Stegun (7.1.26) error-function approximation.
US adult weight figures: CDC / National Health and Nutrition Examination Survey (NHANES), Anthropometric Reference Data.Body-weight distribution modelled as lognormal (the standard approach for right-skewed anthropometric data).Frequently asked questions about the free weight percentile calculator
About this weight percentile calculator
This weight percentile calculator runs entirely in your browser — your weight never leaves your device. It models adult weight as a lognormal distribution and reads your weight off the US curve for your sex, updating instantly as you type.
Calculators Cloud offers 400+ free tools with no sign-up. The Health calculators shelf includes the BMI, height percentile, and healthy weight tools alongside this one. Or browse the full calculator directory.