Free AI and LLM tools

Practical, browser-based calculators and references for choosing models, planning prompts, and understanding how LLM APIs work.

Tier 1

LLM API Cost Calculator

Estimate team API spend across supported models and providers.Open tool

Tier 1

Token Counter

Estimate token, word, and character counts locally across model families.Open tool

Tier 1

Tokens ↔ Words Converter

Convert approximate tokens, words, and characters by model family.Open tool

Tier 1

LLM Pricing Comparison

Sort and filter current per-token model prices and context windows.Open tool

Tier 1

Context Window Comparator

Compare model context limits and test whether a document fits.Open tool

Tier 1

Subscription vs API Cost

Compare monthly consumer subscriptions with estimated API usage.Open tool

Tier 2

Single-Prompt Cost Calculator

Estimate one prompt and response across every supported model.Open tool

Tier 2

AI Model Comparison Tool

Compare model specs, prices, and context windows side by side.Open tool

Tier 2

Prompt Template Library

Search reusable prompt templates for coding, writing, analysis, and agents.Open tool

Tier 2

JSON Schema Validator

Validate a JSON Schema or tool definition directly in your browser.Open tool

Tier 2

Markdown Previewer

Preview AI-generated Markdown with tables, lists, and code.Open tool

Tier 2

RAG Chunk Budget Planner

Plan retrieval chunk sizes around a model’s context window.Open tool

Tier 2

AI/LLM Glossary

Plain-language definitions of common AI and LLM terms.Open tool

Tier 2

Rate Limit Calculator

Estimate throughput, minimum duration, and safe concurrency.Open tool

Tier 2

AI Output Diff Tool

Compare two AI responses and see word-level differences.Open tool

Bring your keys. Keep your savings.