All 141 tools / Research and usability testing
Score SUS results and work out sample sizes for usability tests, A/B tests and surveys.
Usability numbersFreeFor researchers, product teams and designers
60/day
free runs a day, no sign-in.
Before: what you give it
The example input, as typed in. You type in numbers or values.
mode: sus responses: 4 2 4 1 5 2 4 2 4 2 3 3 4 2 4 3 3 2 4 3 5 1 5 1 4 1 5 2 5 1
After: what comes back
The first lines of a real run on that input. Nothing here is edited by hand.
SUS 79.2 from 3 participants, 95% interval 38.8 to 100 (sd 16.3) Grade B on the Sauro and Lewis curve; the adjective scale calls it excellent; about the 81st percentile against the 68-point average. Per participant: 80, 62.5, 95 With 3 participants the interval is wide; treat the score as a direction and not a benchmark. Scoring: odd items score answer minus 1, even items score 5 minus answer, the sum is multiplied by 2.5. Percentile assumes the published mean 68 and sd 12.5. A SUS score says how usable people found it overall and not what to fix.
What you get
SUS score with grade, percentile and 95% interval, or the sample size needed, with the formula
What it cannot do
Needs ten whole-number answers from 1 to 5 per SUS row; the problem-discovery model assumes every person finds problems equally often.
Who it is for
- Researchers
- Product teams
- Designers
Free and Pro
| Free | 60 runs a day per IP address. |
|---|---|
| Pro | No daily limit, 300 requests a minute. |
Use it from your assistant
The tool is called usability_stats. Connect the server once, then ask for it by name or just describe the job. Install steps for each app.
claude mcp add --transport http designers https://designers.allthepossibles.com/mcpcurl -X POST https://designers.allthepossibles.com/api/usability-stats -H 'content-type: application/json' -d '{"mode":"sus","responses":"4 2 4 1 5 2 4 2 4 2\n3 3 4 2 4 3 3 2 4 3\n5 1 5 1 4 1 5 2 5 1"}'Try it here
The form starts with the same example input, so you can run it first and then swap in your own.
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