Before you field
Random group assignment generator
Randomly allocate numbered participants to balanced groups and download a CSV. Free, with no sign-in or participant names required.
No login required. Calculations run in your browser.
Uses numbered placeholders only. Map these numbers to your roster privately, in a fixed order decided before generating. Nothing is uploaded or saved by this tool.
How this tool works
The generator creates nearly equal group sizes, then shuffles group assignments using Fisher–Yates and the browser’s cryptographic random-number generator. Random integer draws use rejection sampling to avoid modulo bias. If the participant count does not divide evenly, the extra places go to randomly selected groups.
Decide your roster order first. Participant 1 in the CSV means the first person on that fixed roster, not a name entered into this tool. Keep the mapping privately. With 20 participants and two groups, each group receives 10 participants; with 21 participants, one receives 11.
Save the CSV before leaving the page. Generating again creates a new allocation; the tool does not preserve a seed or allocation history. Do not repeatedly regenerate to obtain an outcome you prefer.
The tool generates a sequence you can apply to a fixed roster or in blocks as participants arrive. It does not stratify by participant characteristics, conceal allocation, or configure a Plumeform survey. To assign conditions inside a live survey, use its experiment settings.
A useful next step
Understand assignment, conditions, and analysis before launching.
Compare the two arms once the responses have arrived.
Learn which randomization technique matches your research question.
Start
Put it into practice in your next survey.
100 responses a month on Free, and no credit card. Pro is $15 a month for 10,000 responses.