How Much Does It Cost to Run an AI Chatbot?

The honest answer is a range so wide it surprises most founders: the same chatbot, serving the same users and answering the same questions, runs $5.04 a month on the cheapest model we price and $1,080 on the most expensive. The cost formula is simple: users × requests per user × (input tokens × input rate + output tokens × output rate). Everything else is picking the numbers honestly.

A realistic example, priced three ways

Work a realistic example: a customer support bot for a product with 5,000 monthly users, each triggering about 8 requests a month, with a 1,200 token prompt (system instructions plus knowledge base context plus the customer's message) and 300 token replies. That is 40,000 calls, 48 million input tokens, and 12 million output tokens per month. On Mistral Small 3.2 2506, the cheapest model in our basket, that workload runs $5.04 a month. Half the models we price run the same bot for between $21.30 and $180.00. On Claude Fable 5, the most expensive we price, the identical bot costs $1,080. Same bot, same users, same questions, and a 214x spread decided entirely by which model answers.

Four levers that close the gap

Four levers close that gap without hurting quality. First, model tier: most support conversations are routine, and budget models handle them well. Second, prompt caching: that 1,200 token prefix is mostly identical between calls, and cached input can cost 90% less. Third, history discipline: resending the whole conversation each turn silently doubles or triples input volume. Fourth, down-routing: answer easy questions with a cheap model and escalate only the hard ones.

The Customer Support Bot preset in the advanced calculator loads this exact scenario; change the sliders to match your product and the ranking updates instantly.