The latest articles on DEV Community by Calculator Flux (@calculatorflux). https://dev.to/calculatorflux https://media2.dev.to/dynamic/image/width=90,height=90,fit=cover,gravity=auto,format=auto/https:%2F%2Fdev-to-uploads.s3.amazonaws.com%2Fuploads%2Fuser%2Fprofile_image%2F3977770%2F95c502d3-d0f7-46ad-9efb-29ad8eeb4810.png https://dev.to/calculatorflux en Calculator Flux Wed, 10 Jun 2026 13:13:37 +0000 https://dev.to/calculatorflux/how-i-built-166-free-calculators-with-nextjs-and-what-i-learned-10kg https://dev.to/calculatorflux/how-i-built-166-free-calculators-with-nextjs-and-what-i-learned-10kg <p>I spent the last few months building <a href="https://calculatorflux.com/" rel="noopener noreferrer">CalculatorFlux</a>, a free calculator platform with 166 tools covering payroll, finance, health, math, and construction. Here is what I learned along the way.</p> <p>Why Next.js</p> <p>App Router made it easy to give each calculator its own route, metadata, and JSON-LD schema without any extra config. Static generation meant every page loads fast with no server delay.</p> <p>All calculators run client-side</p> <p>Every calculator runs entirely in the browser. No API calls, no server, no database. The user's numbers never leave their device. This was a deliberate privacy decision and it also made hosting much simpler.</p> <p>50 state paycheck calculators</p> <p>The hardest part was building paycheck calculators for all 50 US states. Each state has different tax brackets, flat rates, or no income tax at all. I built a shared calculation engine and passed state-specific tax tables as config objects.</p> <p>SEO at scale</p> <p>Each calculator page has its own title, meta description, canonical URL, and structured data. Blog posts live at /resources/[slug] and link back to related calculators.</p> <p>The result</p> <p>166 free calculators, all 50 US states covered, updated for 2025-26 tax rates.</p> <p>Check it out at calculatorflux.com. Feedback welcome.</p> webdev ai programming productivity