I Built a Free Statistics Calculator with Next.js — Here's What I Learned

As a developer who also does research, I got tired of switching between SPSS, R, and Excel just to run basic statistical tests. So I built StatMate — a free, browser-based statistics calculator that handles 20 different tests and outputs APA-formatted results. Here's the story of how I built it and what I learned along the way. The Problem Every semester, thousands of students and researchers face the same struggle: SPSS costs $100+/month R has a steep learning curve Excel can't format APA tables automatically Online calculators only handle one test at a time I wanted to build something that just works — paste your data, pick a test, get properly formatted results. The Stack Next.js 16 with Turbopack for fast builds TypeScript for type-safe statistics calculations Tailwind CSS v4 for styling next-intl for trilingual support (English, Korean, Japanese) All statistics computed client-side in the browser — no data leaves your machine What It Does StatMate currently supports 20 statistical