About Us
Built for Researchers.
Verified by Standards.
Researchtoolslab exists because free online calculators have a quality problem. Most give you a number with no formula, no verification, and no explanation. We built something better — tools that show their work, cite their sources, and match what university-standard software produces.
Our Mission
Research methodology tools should not be locked behind expensive software licenses or cluttered with ads. Every student writing their first thesis, every public health researcher in a low-income country, every analyst preparing an ethics board submission deserves access to accurate statistical tools — for free.
We build each calculator to the standards that academic journals and institutional review boards actually require: transparent formulas, verifiable outputs, citable sources, and results that match G*Power, WHO STEPS tables, OpenEpi, and other gold-standard references.
Our Verification Standard
Every research calculator on Researchtoolslab is verified against at least two independent reference tools before publication. Our sample size calculator alone passed 47 out of 47 verification checks against G*Power 3.1, WHO STEPS tables, OpenEpi, and Epi Info.
Where the standard normal approximation underestimates true sample size (particularly at 99% confidence), we apply calibrated additive corrections derived from comparison against G*Power's exact non-central distribution calculations. These corrections are documented and available in our methodology page.
Formulas used: Cochran (1977) for survey sample sizes, Cohen (1988) for experimental designs and effect sizes, Kelsey/Schlesselman (1982) for clinical trials, Fisher's z-transformation for correlation studies. Every result page cites the original source.
Our Principles
- 01Formula TransparencyEvery result shows the exact formula used, all variable definitions, and the original academic reference. You can verify every number independently.
- 02No BarriersNo account. No email address. No subscription. No freemium wall. All calculations run entirely in your browser — nothing is sent to a server.
- 03Thesis-Ready OutputResults include a pre-formatted methodology paragraph ready to paste into research proposals, ethics board applications, or journal submissions.
- 04Honest LimitationsWhere estimates are involved (creator earnings, financial projections), we show ranges and clearly label them as estimates, not guarantees.