Paste your text to count tokens and estimate API costs across 12 popular AI models. Token counts use the standard BPE estimation (~4 chars per token).
Estimate how many output tokens the model generates.
Estimated API cost for 0 input tokens + 0 output tokens (1x ratio).
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Most AI models use BPE (Byte-Pair Encoding) tokenization where 1 token is approximately 4 characters or 0.75 words in English. This tool uses that heuristic to estimate token counts. Code and non-Latin text may use more tokens per character.
This estimator is accurate to within 5-10% for English text. For exact counts, each model has its own tokenizer (e.g., tiktoken for GPT, Claude's tokenizer for Claude). The estimates are reliable enough for cost planning.
Pricing reflects model size, compute requirements, and market positioning. Larger models (GPT-4o, Claude Opus) cost more but produce higher quality output. Smaller models (GPT-4o Mini, Gemini Flash) are cheaper and faster for simpler tasks.
The output ratio estimates how many tokens the model generates relative to your input. A ratio of 1x means the output is approximately the same length as the input. For summarization tasks, use 0.25-0.5x. For code generation or creative writing, use 2-4x.