System Usability Scale (SUS) usability testing is a quick method to assess how usable a system is. It uses a 10-item questionnaire with alternating positive and negative statements. Each item is rated on a 5-point Likert scale (1 = Strongly Disagree, 5 = Strongly Agree):
I think I would like to use this system frequently.
I found the system unnecessarily complex.
I thought the system was easy to use.
I think I would need help to use this system.
I found the functions well integrated.
I thought there was too much inconsistency.
I would imagine most people could learn this quickly.
I found the system very cumbersome to use.
I felt very confident using the system.
I needed to learn a lot before using it.
System Usability Scale (SUS) usability testing is a quick, reliable method for evaluating the usability of a product or system. It involves a 10-item questionnaire with five response options ranging from "Strongly Agree" to "Strongly Disagree." Participants complete the SUS after using the product, providing insight into the system’s overall usability. SUS is technology-agnostic and can be used for websites, apps, hardware, or software. Its results yield a score from 0 to 100, helping teams benchmark usability and identify areas for improvement. Simple, cost-effective, and widely adopted, SUS is a valuable tool in user-centered design processes.
Scoring:
For odd-numbered questions: subtract 1 from the user score.
For even-numbered questions: subtract the score from 5.
Add all adjusted scores and multiply the total by 2.5 to get a score out of 100.
A SUS score above 68 is considered above average usability.
