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System Usability Scale · Free

Score your product’s usability in minutes.

Enter or import your participants’ answers and get the overall SUS score, letter grade, percentile, adjective rating, and a per-question breakdown — the whole System Usability Scale, done for you.

Calculate your SUS free →How it works ↓

68

is the average SUS across 500+ products.

See how yours compares — with a grade, percentile, and adjective.

The metric

One number for “how usable is it?”

The System Usability Scale is a short, ten-item questionnaire run at the end of a usability session. It turns subjective impressions into a single, reliable 0–100 score you can track over time, compare across releases, and benchmark against industry norms. It won’t tell you why something is hard to use — but it tells you, dependably, whether it is.

The instrument

The ten statements

Each is answered on a 1–5 scale from strongly disagree to strongly agree. Odd items are positive, even items negative — the alternation is deliberate, and the scoring handles it for you.

  1. 1I think I would like to use the system frequently.
  2. 2I found the system unnecessarily complex.
  3. 3I thought the system was easy to use.
  4. 4I think that I would need the support of a technical person to be able to use the system.
  5. 5I found the various functions in the system were well integrated.
  6. 6I thought there was too much inconsistency in the system.
  7. 7I would imagine that most people would learn to use the system very quickly.
  8. 8I found the system very cumbersome to use.
  9. 9I felt very confident using the system.
  10. 10I needed to learn a lot of things before I could get going with the system.
How it works

From answers to a grade

The tool scores every participant, averages them, and translates the result into the readings teams actually use:

  • A

    90–100

    Best imaginable — top percentile.

  • B

    80–90

    Excellent, comfortably acceptable.

  • C

    70–80

    Good, acceptable — around and above the 68 average.

  • D

    60–70

    OK, but marginal — worth attention.

  • F

    below 60

    Not acceptable — real usability problems.

You also get a percentile rank, an acceptability rating, an adjective from “Worst imaginable” to “Best imaginable,” the Usability and Learnability sub-scores, and a per-question answer distribution.

Run your numbers.

Create a free account, add your participants, and read your SUS in minutes — grade, percentile, and breakdown included.

Calculate your SUS free →