Free survey and research calculators
Free tools for survey and market research work: how many responses you need, what margin of error you have, whether the gap between two results is real, what price to charge, which standard questions to ask and how to brief a study. They run in your browser and send nothing anywhere.
PulseLake offers free tools for survey and market research: sample size, margin of error and significance calculators, Van Westendorp and Gabor-Granger pricing calculators, a bank of standard survey questions and a research brief generator. Each shows its method and runs in your browser.
Survey sample size calculator
How many completed responses do you need? Set the confidence level, margin of error, expected proportion and, if you know it, the population.
Open the toolMargin of error calculator
What margin of error does your sample give you? Enter the sample size, confidence level and proportion, and optionally the population.
Open the toolSurvey significance calculator
Is the gap between two segments or waves real or noise? A two-proportion z-test with the difference, z, p-value and a plain-English reading.
Open the toolVan Westendorp price sensitivity calculator
Paste or load answers to the four Van Westendorp price questions and get the four price points, an acceptable range and a chart.
Open the toolGabor-Granger price calculator
Enter the share of respondents who would buy at each price and get the demand curve, the revenue-maximising price and, with a unit cost, the profit-maximising price.
Open the toolSurvey question bank
Standard, widely used survey questions grouped by purpose, with exact wording, scale, when to use each, a common bias to avoid and its source.
Open the toolResearch brief template
Turn a research request into a clear brief: objective, decision, audience, method, timeline and deliverables, ready to copy.
Open the toolHow do the tools work?
Each tool is a static page with a small script written in plain JavaScript, with no libraries and no third-party requests. The statistics live in one tested module, and the page shows the working so you can check any result by hand. The normal distribution used for critical values and p-values is computed in code, so any confidence level works, not just 90%, 95% and 99%.
Which methods and formulas do they use?
- Sample size: n₀ = z² × p × (1 − p) ÷ e², with n = n₀ ÷ (1 + (n₀ − 1) ÷ N) for a small, known population (Cochran, 1977).
- Margin of error: e = z × √(p × (1 − p) ÷ n), times √((N − n) ÷ (N − 1)) for a finite population.
- Significance: z = (p₁ − p₂) ÷ √(pooled p × (1 − pooled p) × (1 ÷ n₁ + 1 ÷ n₂)), with a two-sided p-value from the normal distribution.
- Van Westendorp: four cumulative curves of the share of respondents against price (too cheap, cheap, expensive, too expensive), and the prices where they cross (Van Westendorp, 1976).
- Gabor-Granger: revenue per respondent = price × share who would buy, and profit per respondent = (price − unit cost) × share (Gabor and Granger, 1966).
The sample size, margin of error and significance tools assume simple random samples, and the pricing tools use stated preferences. Each tool page explains when that is not good enough.
Can I link to or embed the tools?
Yes. Every tool page has ready-made HTML to link to it with attribution and a plain-text citation. Every calculator and the research brief template can also be embedded in an iframe on your own site, free of charge, as long as you keep the credit link beneath it.
Frequently asked questions
Are the calculators free?
Yes. They are free to use with no sign-up. You can also link to them, cite them or embed them on your own site; the only condition for embedding is to keep the credit link under the calculator.
Is anything I enter sent or stored?
No. The calculations run in your browser with plain JavaScript, and the pages make no requests with what you type, including data you paste or load from a file. Close the page and it is gone.
Which formulas do the calculators use?
Cochran's formula with the finite population correction for sample size, the standard error of a proportion for margin of error, the pooled two-proportion z-test for significance, cumulative curves and their crossings for Van Westendorp, and price times share for Gabor-Granger. Each page shows its formula in plain text, a worked example and its references.
How do I know the numbers are right?
The calculations are checked by automated tests against published reference values, such as 385 responses for 95% confidence and ±5 points, 278 for a population of 1,000, critical values of 1.645, 1.960 and 2.576, and z-tests, price points and revenue-maximising prices worked by hand. The normal distribution is computed directly, not read from a rounded table.
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