FreeStatisticalTools A/B test calculator vs PostHog
Both are in A/B testing and Web analytics. Here is how their plans, prices and features compare, taken from each vendor's own site.
| FreeStatisticalTools A/B test calculator | PostHog | |
|---|---|---|
| Starting price | Free plan | Free plan |
| Free plan | Yes | Yes |
| Free trial | Not stated by the vendor | Not stated by the vendor |
| Plans | Free ($0) | Free ($0); Pay-as-you-go (Same free tier each month, then pay for usage) |
| Fees and pricing notes | None stated | Same free tier each month, then pay for usage |
| Best for | Not stated | Not stated |
| 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 | Product and web analytics, 1M events a month free; Session replay, 5,000 recordings a month free; Feature flags (1M requests free) and experiments; Surveys and error tracking |
| Checked on | 2026-10-22 | 2026-10-03 |
Prices change; confirm on the vendor's site before you buy. Full details and sources are on each tool's page.
FreeStatisticalTools A/B test calculator
- 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
PostHog
- Free tier with no credit card that renews monthly, not a trial
- Usage stops at the free limits, so no surprise bills
- Unlimited team members
Trade-offs
- The free plan has 1 project and 1-year data retention
- Pay-as-you-go has no flat price, so cost depends on usage across products
- Platform packages (SSO, audit logs, custom roles) are sold separately