IIF Certified Assessment
Start IQ Test
IIF Certified Assessment
Convert a score to a percentile — or a percentile back to a score — and see how much of that number is actually solid.
In a room of 100 people, about 50 would score below IQ 100 — and the median sits at the tick on the ring.
Shaded area is everyone scoring below IQ 100. Hover the chart to read any point.
| IQ | Percentile | Rarity | Band |
|---|---|---|---|
| 70 | 2.275% | 1 in 44 below | Below average |
| 85 | 15.866% | 1 in 6.3 below | Average |
| 100 | 50.000% | 1 in 2 | Average |
| 115 | 84.134% | 1 in 6.3 above | Above average |
| 130 | 97.725% | 1 in 44 above | Gifted |
| 145 | 99.865% | 1 in 741 above | Highly gifted |
No test returns one true value. Drag reliability to see the range widen.
A score of 100 from a test with reliability .90 really means 91–109 — it sits inside 1 band.
Identical performance, three rulers.
A small difference with a real consequence, and most sites state it backwards. IQ 130 is the 97.725th percentile. The 98th percentile is 130.81.
| Percentile | SD 15 | SD 16 | SD 24 (Cattell III B) |
|---|---|---|---|
| 50th | 100.00 | 100.00 | 100.00 |
| 75th | 110.12 | 110.79 | 116.19 |
| 90th | 119.22 | 120.50 | 130.76 |
| 95th | 124.67 | 126.32 | 139.48 |
| 98th — Mensa | 130.81 | 132.86 | 149.29 |
| 99th | 134.90 | 137.22 | 155.83 |
| 99.9th | 146.35 | 149.44 | 174.17 |
This is why Mensa publishes a percentile requirement rather than a score, and why its accepted numbers differ per test — 132 on a Wechsler test, 148 on Cattell III B. Same ability, different rulers.
This calculator is exact. Give it a number and it will place that number on the curve to three decimals. What it cannot do is check where the number came from — and a score from an untimed quiz that hands out 130s will convert just as confidently as one from a properly normed assessment. The arithmetic is only ever as honest as its input.
Scored on the standard scale, mean 100 and standard deviation 15 — the same scale this calculator defaults to.
Enter it in the calculator above and it is computed instantly. As a guide on the SD 15 scale: IQ 100 is the 50th percentile, 115 is the 84.1st, 130 is the 97.7th and 145 is the 99.9th. Your percentile is simply the share of the population scoring below you. To see the same figure drawn on the distribution rather than as a number, use the IQ bell curve.
This is the single most common mix-up here, and the two are unrelated. A percentage is how much of the test you got right. A percentile is how many people you scored above. Answering 70% of the questions correctly does not put you at the 70th percentile — depending on how hard the test was, it could be the 40th or the 95th. IQ scoring only ever reports the second kind, which is why how IQ tests work spends so long on norming.
On the SD 15 scale the 98th percentile is an IQ of 130.81, not 130. IQ 130 is actually the 97.725th percentile. The difference matters because the 98th percentile is the published entry requirement for Mensa, which is why its accepted scores are 132 on a Wechsler test and 148 on Cattell III B. The full table sits in the section above, and the IQ score converter moves a score between those scales for you.
The 98th, which is the top 2% of the population. Mensa publishes a percentile requirement rather than a single IQ number precisely because the number depends on the scale — 130.81 on SD 15, 132.86 on SD 16, 149.29 on Cattell III B. Note that we are describing their published threshold, not offering a qualifying test: admission requires supervised testing through Mensa or an approved psychologist, and no online result is accepted.
An IQ of 130 on the SD 15 scale is the 97.725th percentile, so roughly 1 in 44 people score that high or higher. Rarity figures beyond about IQ 145 should be treated with caution, because they are extrapolated from the normal curve rather than counted from real test data. The bell curve tool shows how quickly the tail thins out, and average IQ by country puts population-level figures in context.
Yes. The calculator above works in both directions — type a percentile into the second field and it returns the IQ score that reaches it, on whichever scale you select. This uses the inverse normal distribution. If you want to move a score between two different scales rather than to a percentile, that is the IQ score converter.
Because tests use different standard deviations. The 98th percentile is 130.81 on an SD 15 test, 132.86 on an SD 16 test and 149.29 on Cattell III B, which uses SD 24. The ability is identical; only the scale changes. This is why an IQ number means nothing without the scale it was measured on — how IQ tests work explains where standard deviations come from, and the IQ comparison tool shows two scores side by side.
Your percentile is always measured against your own age group, so it does not drift simply because you age. What can change is the underlying performance behind it, and different abilities move at different rates across a lifetime. IQ and age breaks that down, and regression to the mean explains why an unusually high or low result tends to move back toward your average on a retest.
No. The calculator runs entirely in your browser — nothing you enter is transmitted, logged or saved, and no account is required to use it. Our Security and Privacy Policy sets out how the rest of the site handles data.
This calculator interprets a number you already have. Take the assessment to measure one properly — score, percentile and full performance report.
