FreeStatisticalTools A/B test calculator
A free calculator for judging A/B test results and the difference between two conversion rates.
Best for: marketers checking whether an A/B test difference is statistically significant, free with no signup
- Starting price
- Free plan
- Free plan
- Yes
- Free trial
- Not stated by the vendor
- Checked on
- 2026-10-22
A free online calculator for A/B tests. Enter visitors and conversions for variants A and B, or paste or upload the data, and it shows each conversion rate, the relative uplift, the difference with a 95% confidence interval, the z value and p-value, a chance that B beats A and a significant or not decision at 90, 95 or 99% confidence. No sign-up is needed, and the page says the data stays in your browser.
Key features
- Conversion rate for each variant, relative uplift and the difference (B minus A) with a 95% confidence interval
- z value, two-tailed p-value and a significance decision at 90, 95 or 99% confidence
- A "chance B beats A" figure
- Paste from Excel or upload CSV, TSV or Excel data
- Data stays in the browser, per the page
What stands out
- Free with no sign-up
- Gives the p-value, confidence interval and uplift, not just a yes or no
- Warns against stopping a test early just because it reaches significance
Trade-offs
- The page does not name the test it uses; the results are consistent with a two-proportion z-test
- The example data on the page is meta-analysis data, not visitor and conversion counts
- It does not explain how the "chance B beats A" figure is calculated
Pricing
| Plan | Price | Fees | Includes |
|---|---|---|---|
| Free | $0 | Not stated |
|
The calculator is free with no sign-up. The page promotes a free checklist that asks for an email, plus a newsletter and other free tools. The site is credited to Bibin Xavier (copyright 2026). A third party suggested the listing and said they have no ownership or affiliation. The method is not named on the page; the figures shown are consistent with a two-proportion z-test.
Checked 2026-10-22. Source: freestatisticaltools.com. Prices change; confirm on the vendor's site before you buy.
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