Calculate how many survey responses you need
Calculating the ideal number of survey responses is more than just estimating how many surveys to send out. It begins with determining the size of your target population and the level of accuracy you expect from your survey results.
To estimate your survey sample size, follow our five-step process:
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Step 1 Identify the size of the target population
Fewer than 2,000 people Send the survey to as many as possible
More than 2,000 people Send the survey to a subset of the population
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Step 2 Determine the level of accuracy required
Confidence Level + Confidence Interval = Accuracy
The “plus-or-minus” figure reported along with polls is known as the margin of error, or confidence interval, and indicates the accuracy of the data. A survey result of 60% with a 5% margin of error indicates that the true value lies somewhere between 55% and 65%.
Confidence level is the other measurement that will affect the number of respondents you need. It measures the certainty that the survey results are within the margin of error. Most researchers use a 95% confidence level.
When you put the confidence level and confidence interval together, you can be 95% sure that the survey results fall within the margin of error (between 55% and 65% in the example above).
The wider the confidence interval that you are willing to accept, the more certain you can be that the answers of the entire population would fall within that range.
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Step 3 Estimate the number of completed surveys required
Using the chart below, select your approximate target population; then choose your margin of error to estimate the number of completed surveys you'll require.
| Size of Customer Base |
Sample Size Needed
(95% Confidence Level) |
| +/-3% |
+/-5% |
+/-10% |
| 2,000 |
696 |
323 |
92 |
| 3,000 |
788 |
341 |
94 |
| 5,000 |
880 |
357 |
95 |
| 10,000 |
965 |
370 |
96 |
| 20,000 |
1,014 |
370 |
96 |
| 50,000 |
1,045 |
382 |
96 |
| 100,000 |
1,058 |
383 |
96 |
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Step 4 Estimate the survey response rate
Estimating your response rate will help you determine the total number of surveys you'll need to send out to obtain the required number of completed surveys.
Response rates vary widely depending on a number of factors. For online surveys in which there is no prior relationship with recipients, response rates can be as high as 20% to 30%.
Factors that can affect your survey response rate include the relationship with your target audience, survey length and complexity, incentives, and survey topics.
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Step 5 Calculate sample size of survey
Divide the number of completed survey responses you need by your estimated response rate to calculate your sample size.
Need more people to take your surveys? Zoomerang Sample can help.
Zoomerang Sample is a group of more than 2 million people who have agreed to take surveys just like yours. They have all “opted in” and receive an incentive for completing your survey. Each survey taker has been profiled against hundreds of demographic, lifestyle, occupational and geographic data points so that you can survey the exact group whose feedback matters to you. The best part is we manage all of the details so you dont have to!
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