Estimate
Where chatbot tokens go
Every request resends the system prompt, tool definitions and whatever history you include, so a long conversation gets more expensive with each turn. The cheapest wins are usually a shorter system prompt, a sliding window or summary of older turns, a cap on output length, and prompt caching for the stable prefix.
- Rule of thumb for English: 1 token is about 4 characters or 0.75 words. Spanish and code use somewhat more tokens per word.
- For exact counts use the tokenizer library or the token-count endpoint published by your model provider.
Related: Conversation flow designer, AI chatbots and agents guide.