AI Agent Cost per Month: The Token Maths, Worked Out
A four-message support chat with a tool-using AI agent can send the model more than 45,000 input tokens. That's about twelve times Anthropic's own estimate of roughly 3,700 tokens for a support conversation ( Anthropic pricing ). Nothing is broken: each turn simply resends everything that came before it. That's why most guides to AI agent cost per month give you wide ranges instead of a number.…
AI agents can generate over 45,000 input tokens in a single four-message support chat, which is about twelve times the estimated 3,700 tokens according to Anthropic pricing. This is due to the model repeating all previous turns in each new turn, resulting in high conversation history costs. Most AI agent cost per month articles provide a range rather than a specific number, as the per-token price does not accurately reflect actual spend.
The four factors impacting the monthly bill are conversations per month, model calls per conversation, input tokens per call, and tools. Token counts vary between different models, so it's essential to use the actual model for your calculations. The monthly run cost formula is: N × (I × p_in + O × p_out) / 1,000,000 × (1 + r) + fixed costs.
In a small-business support bot example, the monthly cost on Claude Haiku 4.5 is approximately $170.94, with history tokens playing a significant role in the overall cost.
Written by urgent.news from Dev.to's reporting — not their text. Machine-written — may contain errors; check the original before relying on it.
