Who built this
ProbLab is run by a small, named team: a working statistician (the math side), an educator (the "explain it like I'm 15" side), and a tabletop game designer (the "make it actually fun to use" side). We maintain the site part-time and publish under our real names on the contact page.
Why we built it
Most "probability calculator" sites we found in 2024–2026 do one of three things:
- They give you a single number with no context — so you don't know whether to trust it or act on it.
- They show a generic ad-laden interface that buries the formula and copies textbook examples verbatim.
- They try to sell you a "winning system" by abusing math.
None of those match what an actual person with an actual question (a teacher prepping a class, a poker player checking gut feel, a PM sizing an A/B test) actually needs. ProbLab is the calculator we wanted ourselves.
Who it's for
- Educators and students. Visualizations make formulas stick. Each tool has a "what this means" section written for a curious 16-year-old, not a math PhD.
- Gamers. D&D players running exploding dice, poker players computing hand equity, board-gamers checking ruin probabilities. We include game-specific presets (5e advantage, World of Darkness dice pools, etc.).
- Analysts and product managers. Confidence intervals, A/B sample sizing, chi-square independence, Bayesian updates with prior/posterior — the standard inference toolbox without paying for a stats SaaS.
- Curious adults. "What does it mean that the test is 95% confident?" — every result page tries to answer the question behind the calculation.
What we intentionally don't do
- We don't sell betting picks or claim any tool "predicts" future outcomes. Probability calculators describe models; they do not predict.
- We don't collect personal data. There's no login, no email capture, no behavioral tracking beyond what Google AdSense itself does. See Privacy Policy.
- We don't show ads that look like buttons, "Download" prompts, or fake system notifications. See Disclaimer for the full standard.
- We don't promise "secret" math. Every formula is shown or linked in the tool's explanation section.
How we handle corrections
If you find a math error, a broken link, or an unclear explanation, we fix reported issues within seven days. Each tool page has a "Report an error" mailto at the bottom. We document fixes in the changelog below.
Changelog
- 2026-09-16 — Initial public release of 22 calculators, About / Privacy / Disclaimer pages.
- 2026-09-02 — Internal review pass. Removed a non-essential third-party script that was inflating load time.
Contact
General questions, corrections, partnership ideas: hello [at] problab.example. (Replace the obvious placeholder with a real address before going to production.)