Free survey tools
Work out the numbers before you launch.
Estimate sample size and survey length, prepare questions, or check your results. These tools run in your browser without an account and explain the assumptions behind each calculation.
Before you field
Estimate the responses you need and the time each person will spend answering. Check those assumptions with a pilot before full collection.
Survey sample size calculator
Estimate the completed responses and invitations you need.
Open toolSurvey completion time estimator
Estimate how long your survey will take to answer.
Open toolRandom group assignment generator
Assign numbered participants to balanced groups and download the allocation.
Open toolWhile you write the questions
Choose clear scale labels and check that each question asks one thing. Ambiguous wording makes answers harder to interpret.
Once the answers are in
Calculate scores and compare groups with the sample size and uncertainty in view. Each tool explains what its result can and cannot tell you.
System Usability Scale calculator
Score ten-item SUS responses and inspect individual scores.
Open toolKano model classifier
Classify paired feature reactions and calculate coefficients.
Open toolVan Westendorp price sensitivity calculator
Plot pricing curves and inspect the acceptable-range crossings.
Open toolMargin of error calculator
Estimate the margin of error around a survey percentage.
Open toolSurvey significance test calculator
Compare two groups using their response counts.
Open toolNPS calculator
Calculate NPS, its response breakdown and a confidence interval.
Open toolWhat they are for
Four things to plan before collecting answers.
Use the calculators to plan collection and analysis before sharing the survey. A small pilot can help you check assumptions about timing and response rates.
How many responses is enough
Choose a response target based on the precision or difference you need to measure. Allow for any groups you plan to compare and the assumptions of your study design.
Or read the maths, without the jargon.
How long it takes to answer
Completion time sets your incentive on a paid panel and your drop-off everywhere else. Reading load, question type and page count all count, and the estimate is only a starting point: a pilot with five people tells you what the calculator cannot.
Or read what rushing does to the data.
Who goes in which group
Randomly assign participants to conditions and record the assigned group with each response. This tool creates balanced groups from numbered participants.
Or read running it inside a survey.
How to assess a difference
Compare two percentages using the counts behind them. The significance test helps assess the difference under its assumptions, while confidence intervals show uncertainty around each estimate.
Or read precision and what it costs.
Need the reasoning behind the numbers? Read the research guides. For definitions, the survey glossary explains common terms and mistakes to avoid.
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.