AI Token Counter
Estimate token count and API cost for major AI models. Paste your text, see the numbers. Free. No signup.
What are tokens?
Tokens are the units that language models use to process text. A token can be as short as one character or as long as one word. On average, 1 token ≈ 4 characters in English, or about ¾ of a word.
Why token count matters
- API billing — most AI providers charge per token (input + output). Knowing your input token count helps estimate costs before making API calls.
- Context window — every model has a maximum context length. GPT-4o supports 128K tokens, Claude 4.6 supports 200K-1M tokens. Exceeding the limit truncates your input.
- Prompt optimization — shorter prompts cost less and leave more room for the model's response. Token counting helps you trim without losing meaning.
How estimation works
This tool uses a heuristic approximation based on the cl100k_base tokenizer pattern (used by GPT-4 and similar to Claude's tokenizer). For exact counts, use the provider's official tokenizer library. Our estimates are typically within 5% for English text.
Pricing reference (per 1M input tokens)
| Model | Input | Output |
|---|---|---|
| GPT-4o | $2.50 | $10.00 |
| Claude Opus 4.6 | $15.00 | $75.00 |
| Claude Sonnet 4.6 | $3.00 | $15.00 |
| Gemini 2.5 Pro | $1.25 | $10.00 |
| GPT-3.5 Turbo | $0.50 | $1.50 |