AI Token Calculator
Paste your prompt below to see an estimated token count and how much of common model context windows it would use.
| Model | Context window | Estimated usage |
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About this tool
Tokens are the units AI models actually read and bill by, they're not the same as characters or words. This estimates your token count using the common rule of thumb for English text (roughly 4 characters per token), since exact counts depend on the specific tokenizer each model family uses under the hood.
Why this is an estimate, not an exact count
Different model families (GPT, Claude, Gemini, Llama) use different tokenizers, so the same text can produce a different exact token count on each one. Whitespace, punctuation, and non-English text also tokenize less predictably than the simple 4-characters-per-token rule assumes. Treat this as a quick sanity check before pasting a long prompt, not a substitute for a model's official tokenizer.
Context window figures
The context window sizes listed above are commonly published maximums for each model family and can change between model versions, always confirm against the provider's current documentation before relying on them for production use.