AI Agent Cost Calculator
Estimate your monthly LLM API spend and see how much you could save with smart model routing.
Stop estimating. Start tracking actual spend.
This calculator uses averages. Costline shows you real per-agent costs pulled directly from OpenAI and Anthropic — by agent, by model, by day.
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How this calculator works
Token split: We assume 70% input tokens and 30% output tokens per call — a reasonable average for most agent workloads. Adjust as needed for your use case (output-heavy generation tasks will be more expensive).
Pricing: Based on published April 2026 list prices: GPT-4o at $2.50/$10 per 1M input/output, GPT-4o mini at $0.15/$0.60, Claude 3.5 Sonnet at $3.00/$15.00, Claude Haiku at $0.25/$1.25, Gemini Pro at $1.25/$5.00. Prices vary with volume discounts and change over time.
Savings estimate: The routing projection assumes 70% of calls are routed to the cheapest available model in the same family (or the cheapest model overall), with the remaining 30% staying on your primary model. Real savings depend on task mix and quality requirements.
Want actual numbers? Connect your API keys in Costline — we pull real usage data directly from OpenAI and Anthropic and show per-agent breakdowns.