Free Tools for Builders
Free, no-signup interactive tools that run entirely in your browser: generate a spec-correct llms.txt, and more cost, token and decision helpers to come. Nothing you type leaves your machine, and every tool is paired with a plain-language explainer.
llms.txt Generator
Generate a spec-correct llms.txt file for your site in seconds. Free, client-side, copy or download the result. Plus a plain-language explainer of what llms.txt is.
Free tool · 3 min readLLM Cost Calculator
Free LLM API cost calculator. Estimate per-call and monthly cost for Claude, GPT and Gemini, compare two models, and model prompt caching and batch savings.
Free tool · 4 min readToken & Context Window Estimator
Free token counter and context window estimator. Paste text to estimate tokens and see if it fits each model context window for Claude, GPT and Gemini.
Free tool · 4 min readAI Automation ROI Calculator
Free AI automation ROI calculator. Enter hours, people and cost to see time saved, monthly and annual savings, payback period and first-year ROI in seconds.
Free tool · 4 min readWhich AI Coding Tool Should I Use?
Free quiz to find your best AI coding tool. Answer seven quick questions for a personal pick from Claude Code, Cursor, Copilot, Windsurf, Codex CLI or Aider.
Free tool · 4 min read