A small public toolbox, maintained by hand
Free web tools that actually feel fast
No signups, no popups, no dark patterns. Each tool runs in your browser, returns results instantly, and shows the math behind the answer. We pay the bills with non-intrusive ads — that's the whole deal.
Current collection
Tool families
Each family is intentionally narrow: fewer pages, clearer purpose, and no public placeholder tools.
Financial Calculators
Available nowMortgage, auto loan, paycheck, income tax, compound interest. 5 calculators with show-the-math on every result.
Open ->
Format Converters
Available nowTime zone, unit, temperature converters. 80+ time zones with DST handling.
Open ->
Text Utilities
Available nowWord counter, Lorem Ipsum generator, with reading-time estimates.
Open ->
Developer Tools
Available nowJSON formatter, Base64 encoder. Real-time validation, URL-safe variants.
Open ->
AI Utilities
Available nowToken cost calculator, prompt builder, prompt cleaner, and privacy checker. Browser-only, no signup.
Open ->
Editorial rules
Why kdp.cool
- Speed and clarity first. Tools render in under a second and recalculate as you type. No loading spinners on basic math.
- No email walls. We don't gate features behind signups, "premium" tiers, or "free trial" funnels. Everything is free, forever.
- Show the math. Our calculators include a "Show the math" toggle that reveals the formula and intermediate steps. You can verify the answer or learn the method.
- Open source. Code is on GitHub at github.com/kedoupi/kdp-tools. Bug? Open an issue.