About PlainCalc

Clear numbers. Keep more.

PlainCalc is a static, mobile-first hub of free calculators aimed at high-intent questions with less SEO noise than generic “PDF tools” or toy widgets. We focus on marketplace seller economics, paycheck conversion math, and everyday energy costs — topics where a transparent formula and dated assumptions beat a black-box app.

What we believe

People deserve to see the arithmetic. Fee schedules change; labor rules vary; utility rates differ by zip code. Instead of pretending precision, we stamp assumptions with an AS_OF date in code, show disclaimers next to results, and link to official sources when they exist.

No account, no backend (v1)

Calculations run in your browser. We do not require signup. Optional “saved inputs” via localStorage stay on your device if enabled by a tool. The site is designed for Cloudflare Pages: fast, cacheable HTML/CSS/JS.

Expanding the hub

PlainCalc is built so new calculators can be added as additional static pages sharing the same design system, fee constants file, and SEO patterns. Quality over doorway spam — each tool should earn its URL with working math and useful copy.

Contact & trust pages

Read our Privacy Policy (important before AdSense) and Disclaimer. Tool index: all calculators.