What Is Hensachi? From a 20-Person Example to Choosing a University

Hensachi isn't the test score itself — it shows roughly where someone stands among everyone who took the same test. Scoring exactly average gives a hensachi of 50.

The formula: Hensachi = 50 + 10 × (your score − average score) ÷ spread (standard deviation)

Say 20 people take a test, scores range from 40 to 88, the average is 62.05, and the spread is 12.4. A student who scores 75 gets a hensachi of

50 + 10 × (75 − 62.05) ÷ 12.4 ≈ 60.5

That's roughly 4th out of 20 — the top 20% of this group. The same 80 points would give a different hensachi on an easier test versus a harder one. Hensachi isn't measuring "how well you did" in an absolute sense — only where you land relative to that specific group.

Junior high, high school, and university entrance exams: the same hensachi 60 means different things Swap "20 people" for "20 people taking a specific entrance exam," and the makeup of that group of 20 (the population) changes completely depending on the exam stage.

Junior high entrance exams (chūgaku juken): only around 20% of elementary schoolers — an already self-selected, motivated group — actually sit this exam. Landing in the top tier within that already-narrow pool represents a high absolute ability level. High school entrance exams (kōkō juken): nearly everyone in the age cohort takes this, so the population is close to the full range of ability in that grade. The same hensachi 60 reflects a lower absolute level than in junior high entrance exams, simply because the pool is so much broader.

University entrance exams (daigaku juken): limited to those aiming for university — roughly 50-60% of the age cohort. Narrower than high school entrance exams, but not as narrow as junior high entrance exams.

That's why it's commonly said: for the same hensachi of 60, actual ability runs highest for junior high entrance exams, then university entrance exams, then high school entrance exams. Even within university entrance exams, the mock-exam provider changes the number — a real example Comparing Keio University's Faculty of Law (Law department) across two different mock exam providers:

Same university, same department — a 13.5-point gap. Neither number is wrong; they're just different rulers. That means comparing hensachi across universities only makes sense within the same mock-exam provider. If you're taking Kawai Juku's exams, checking your score against a Benesse ranking table won't tell you where you actually stand.

Two more things that are easy to overlook

Number of subjects : A three-subject entrance exam and a five- or seven-subject one aren't measuring the same thing, even at the same hensachi. Someone strong in just a couple of subjects tends to post a higher hensachi on exams that require fewer subjects. Comparing across formats with different subject counts, based on the number alone, is misleading.

Difficulty getting in vs. difficulty once you're in : hensachi only reflects the relative difficulty of admission. It says nothing about how demanding the coursework is afterward, or how hard it is to advance or graduate. A high hensachi doesn't mean things get easier once you're enrolled.

Summary: How hensachi is actually useful

Given all this, hensachi works better as a tool for figuring out two things than as an absolute cutoff for pass/fail:

1. Where you currently stand within that specific population (a relative read on your position)

2. How much growth you need to reach the group you're aiming for (a sense of the remaining distance)

Rather than looking at one number and deciding "this school is out of reach" or "this one's a safe bet," it's worth checking which mock exam and which population the number comes from, and whether the subject count and format actually match your target school — then using it to measure the gap between where you are and where you're aiming. That's the healthier way to hold this number.