Hensachi Calculator — Japanese Standardized Score (偏差値)
Calculate hensachi (Japanese standardized score: 50 = average, 10 points = 1 SD) from your score, mean and SD — or from a pasted list of all scores — with percentile and rank.
🔒 Runs entirely in your browser. Your input and output are never sent to a server or stored — fully private.
Hensachi (偏差値) is the Japanese standardized score used for school and university admissions: 50 = exactly average, and every 10 points = 1 standard deviation. Formula: (score − mean) ÷ SD × 10 + 50.
Hensachi is relative to the specific test population it was computed from — scores from different mock exams (or different providers) are not directly comparable. Percentile assumes an approximately normal score distribution.
About this tool
This hensachi calculator works out a Japanese standard score — the number Japanese students live by at exam time. It rescales your score against the test's mean and standard deviation so that 50 is exactly average and every 10 points equals one standard deviation, then estimates your percentile. Enter your score with the mean and standard deviation, or paste every score in the class and it computes them for you. It runs entirely in your browser, so a list of real exam scores never leaves your device.
Frequently asked questions
How is hensachi calculated?
Hensachi = (your score − mean) ÷ standard deviation × 10 + 50. If you score exactly the average you get 50; one standard deviation above is 60, two above is 70, and below average drops under 50. So a 70 on a test with mean 60 and SD 10 gives a hensachi of 60, which is roughly the 84th percentile if scores are bell-shaped. It measures your position within that specific group of test-takers, not an absolute level of ability.
Can I compare hensachi across different exams?
Not directly. A hensachi is always relative to the population that sat that particular test, so a 60 on an easy school quiz and a 60 on a tough national mock represent very different achievements — the mock's field is stronger. This is why the same student can get different hensachi on different mock-exam brands in the same week. Use it to track your position within one consistent test series, and treat cross-exam comparisons with caution.
Are my scores kept private?
Yes. When you paste a whole class's scores, the mean, standard deviation and each hensachi are computed by JavaScript in your browser — nothing is uploaded or stored. That matters because a list of named exam results is sensitive. And remember a hensachi is one snapshot of relative standing, not a measure of your worth; use it as feedback, not a verdict.