thrive at work/Survey sample size calculator
Free tool · Surveys
Survey sample size and response rate calculator.
Enter how many people you invite and how many answered. See your response rate, how precise the results are and how many responses you need.
By Jerry Fiser, Founder & CEO · Reviewed by Marcin Bulik, Research Director · Updated November 8, 2026
How many responses do I need for an employee survey?
It depends on how many people you invite and how precise you want the result to be. For a margin of error of plus or minus 5 points at 95% confidence, a company of 500 needs about 218 responses, and a company of 5,000 about 357. Small teams need a much larger share of people to answer, because each answer carries more weight.
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- Response rate = responses ÷ people invited × 100.
- Margin of error shows how far the survey result could be from the full answer, by chance alone.
- Smaller groups need a higher share of responses for the same precision.
- A high response rate matters more than the formula: it reduces the risk that non-responders think differently.
- Report results only for groups large enough to protect anonymity.
Calculate your response rate and margin of error.
Change any value; the results update as you type. The link saves your numbers so you can share or bookmark them.
Your survey · change any value
Your response rate
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Response rate = responses ÷ people invited × 100. Margin of error uses the standard formula for a proportion at 50% (the most cautious case), corrected for the size of the group: z × √(0.25 ÷ responses) × √((invited − responses) ÷ (invited − 1)). It only covers chance; it cannot fix bias if the people who did not reply think differently from those who did.
Responses needed by company size.
At 95% confidence, using the cautious 50% assumption.
| People invited | For ± 5 points | For ± 3 points |
|---|---|---|
| 50 | 45 | 48 |
| 100 | 80 | 92 |
| 250 | 152 | 203 |
| 500 | 218 | 341 |
| 1,000 | 278 | 517 |
| 5,000 | 357 | 880 |
| 10,000 | 370 | 965 |
The numbers rise slowly once groups get large: a company of 10,000 needs only a little more than one of 5,000. For small teams, almost everyone has to answer for a precise result, which is one reason to report small teams together rather than separately.
What margin of error means.
If 60% of respondents agree with a statement and the margin of error is plus or minus 5 points, the answer for everyone invited is likely to be between 55% and 65%. “Likely” here means at your chosen confidence level, usually 95%. When two teams differ by less than the margin of error, treat the difference as noise until it repeats in the next survey.
Why response rate still matters.
The margin of error assumes the people who answered are like those who did not. In employee surveys that is often not true: the most disengaged or overloaded people are the least likely to reply. A high response rate reduces that risk more than any formula can correct it. Clear communication about anonymity, a short survey, time to fill it in during work hours and visible action on last time’s results all help. See pulse surveys and employee survey questions.
Group size and anonymity.
Precision is not the only reason to set a minimum group size. People answer honestly only if they trust that no one can identify them. Most survey programs show results only for groups above a minimum number of responses, often five or more, and combine smaller teams. Set this rule before the survey and tell employees about it.
thrive at work measures engagement (purpose, leadership, connection, growth) and capacity (energy, recovery, focus, resilience) in one anonymous assessment: see how the assessment works.
Most engagement problems show up first as falling energy, recovery and focus. thrive at work is a workforce performance platform: an employee engagement platform that also measures capacity to perform, so you can see strain by team before it turns into absence or resignations. Read more about employee capacity.
Common questions
What is a good response rate for an employee survey?
How do I calculate survey response rate?
What margin of error is acceptable?
Does the calculator store my numbers?
See which teams are running low.
A 30-minute call shows what a first engagement and capacity assessment would reveal.