Free tools
AI tools that actually decide things
Instant, no-signup utilities for people building with AI — the numbers behind the buying decision, not another listicle.
16free tools · no signup · web-verified & dated
Start hereThe Frontier IndexThe state of the AI frontier in one place — cheapest models to run, biggest context windows, and how far open weights undercut proprietary APIs. The editorial read the calculators build on.OpenCost calculators
- Calculator
AI Agent Cost Calculator
What does running an AI agent actually cost? Models the context that compounds every step — the reason multi-step agents cost far more than single calls — across GPT, Claude & Gemini.
Open tool - Calculator
Prompt Caching Savings Calculator
How much does prompt caching cut your LLM input bill? Set your reused-prompt size and cache-read discount to see monthly cost with vs without caching — provider-agnostic.
Open tool - Calculator
AI Subscription vs API
Is ChatGPT Plus / Claude Pro worth it, or is the API cheaper for you? Enter your usage to see the monthly cost both ways and the exact break-even.
Open tool - Calculator
AI API Cost Calculator
Estimate your monthly API spend across GPT-4o, Claude, and Gemini from your own usage — ranked cheapest-first.
Open tool - Calculator
Build vs Buy: Local-AI Payback
Enter your monthly API spend → see when an RTX 5090, 4090, or Mac Studio pays for itself vs paying per-API.
Open tool
Side-by-side comparisons
- Table
AI Model Comparison
Context windows, prices, modality, and open-weights status for every major model — filterable, side by side.
Open tool - Table
AI Subscription Comparison
ChatGPT vs Claude vs Gemini vs Perplexity vs Grok — every consumer plan by price, models, and limits.
Open tool - Table
AI Image Generation Cost
Midjourney, DALL·E, Imagen, Ideogram, Leonardo, Firefly + free self-host — by subscription, per-image, and rights.
Open tool - Table
AI Coding Assistant Comparison
Cursor, Copilot, Claude Code, Windsurf, Cline, Zed + more — by price, billing model, and features.
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Hardware & model pickers
- Checker
Local-LLM GPU Checker
Pick your GPU (or enter VRAM) and see exactly which open LLMs you can run locally — and at which quantization.
Open tool - Picker
Which AI Model Should I Use?
Answer a few questions about your use case and budget, get a top pick plus two alternatives with the reasoning.
Open tool - Recommender
What GPU Do I Need?
Pick the model you want to run → the minimum GPU (or Mac) that runs it locally, plus every card that fits.
Open tool - Calculator
Fine-Tuning VRAM Calculator
How much GPU memory to fine-tune a model? Full vs LoRA vs QLoRA side by side, with the minimum GPU each needs.
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Tokens & context
- Counter
Token Counter
Paste any text → exact GPT / Claude / Gemini token count, words, characters, per-model context-window fit, and the cost to send it. Runs in your browser.
Open tool - Converter
Words ↔ Tokens Converter
Convert between words, tokens & characters, and see how much fits in an 8K–1M context window. The quick estimate; for an exact count of specific text, use the Token Counter.
Open tool - Calculator
Context Window Calculator
Will your document fit? Words, pages, or tokens → which models can hold it in one context window, and the cost.
Open tool
Go deeper
The guides behind the numbers. Read the concept, then run the tool.