Survey Invitation Planner

Start with the number of completed responses you want and a response-rate assumption for this audience and channel. This planner estimates invitations; it does not decide your statistical sample size or guarantee participation.

Free, no signup, and everything is calculated in your browser.

Completed responses wantedAssumed response rate (%)Reachable people (optional)

334 invitations

Planning estimate, rounded up. It does not guarantee 100 completions.

At 10%

1,000 invitations

At 25%

400 invitations

At 50%

200 invitations

Change assumptions to compare scenarios. Count unique people, not repeat reminders.

From target completions to invitations

Invitations = target completions divided by the assumed response rate, rounded up to the next whole person. For 100 completions at 30%, plan 334 invitations. At 20%, the same target requires 500. These are planning scenarios, not forecasts with a confidence interval.

Define the denominator consistently. Here the rate means completed responses divided by unique people invited. A rate measured only among delivered emails or people who opened a link is a different assumption. Use a comparable previous survey where possible; do not treat the default as a benchmark.

If your reachable audience is smaller than the estimated invitation requirement, review the target, audience or fieldwork plan. Sending repeat reminders to the same people does not increase the number of unique invitees. This tool does not send messages or create a contact list.

Choose your completion target separately. Representativeness, coverage, nonresponse bias and any required statistical precision are not solved by inviting more people. Use the sample-size tool for a separate precision calculation when its assumptions fit your study.

Questions people ask

What if I do not know the response rate?

Compare plausible scenarios and label them as assumptions. The default 30% is an example, not an industry average or a promise.

Can I use a decimal rate?

Yes, such as 12.5%. The rate must be greater than 0 and no more than 100. The completion target must be a positive whole number.

Does an audience shortfall mean the survey will fail?

It means the audience is smaller than this scenario requires. Revisit the assumptions and collection plan; the estimate alone cannot predict the result.