How to Evaluate the Usability of Your Website Using the System Usability Scale

What is the System Usability Scale (SUS)?

  • Effectiveness: How successfully users can complete their goals, like making a purchase or signing up for a free trial
  • Efficiency: The number of resources (like time and energy) used to achieve those goals
  • Satisfaction: How satisfied users are after using your system

The System Usability Scale questionnaire

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

How to calculate your SUS score

  1. Total up the scores from all odd-numbered questions, then subtract 5 from the total.
  2. Total up the scores from all even-numbered questions, then subtract the total from 25.
  3. Add the results from Step 1 and Step 2, then multiply by 2.5.
  1. (2 + 3 + 5 + 4 + 1) — 5 = 15–5 = 10
  2. 25 — (3 + 5 + 5 + 3 + 4) = 25–20 = 5
  3. (10 + 5) x 2.5 = 15 x 2.5 = 37.5

How to implement your SUS learnings

Improve your website usability

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