How to count AI tokens
Check how many tokens a prompt costs before you send it — for context-window limits, API cost, or fine-tuning data prep.
1. Pick a model
Choose GPT, Claude, Gemini or another model family — each tokenizes text differently.
2. Paste your prompt
Token, character and word counts update live with every keystroke.
3. Check fit & cost
See what share of the context window you're using and an estimated API cost.
Useful for trimming a prompt to fit a model's context window, sanity-checking API costs before a big batch job, or estimating fine-tuning data size. GPT-4o, GPT-5, GPT-3.5 and GPT-4 counts use the same byte-pair-encoding tokenizer those models use internally; Claude, Gemini, Llama and Mistral counts are estimates, since those providers don't publish a downloadable tokenizer. Everything runs in your browser, so even confidential prompts and proprietary code stay private. For plain word and character counts, try the Word Counter.