Agent LaneTool
AI API cost calculator
Estimate what an AI agent or app costs each month in API tokens, then get a spending cap to set before it runs. Enter your provider’s current price. It runs in your browser and nothing is sent anywhere.
Your estimate
- Estimated monthly cost
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- Suggested monthly cap
- –
- Estimated daily cost
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- Suggested daily cap
- –
- Cost per call
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How the numbers work
| Cost per call | (input tokens × input price + output tokens × output price) ÷ 1,000,000 |
|---|---|
| Daily cost | cost per call × calls per day |
| Monthly cost | daily cost × days per month |
| Suggested cap | cost × (1 + buffer %), rounded up to the cent |
Formulas last checked 26 October 2026. Prices are your inputs; this page lists no vendor prices.
Turn the estimate into real limits
- AI agent spend cap calculator: per-payment, daily and monthly caps when agents also make purchases.
- AI agent spending limits: where to enforce caps so the model can’t talk past them.
- What an AI agent costs: the other costs beyond tokens.
- Fund the session ceiling: why the monthly cap is a backstop, not the live brake.
FAQ
- How do I estimate my monthly AI API cost?
- Multiply calls per day by tokens per call, divide by one million, multiply by your price per million tokens, then multiply by the days you run each month.
- Why are input and output tokens priced separately?
- Many providers charge a different rate for tokens you send (input) and tokens the model writes (output), so enter both prices if your provider lists two.
- What monthly spending cap should I set?
- Set the cap a little above your estimate (the default buffer is 25%) so normal months fit and a runaway loop hits the limit.
- Where do I set the cap?
- Set it in your provider’s billing or usage-limit settings, or in code that counts spend before each call, not in the prompt.
- Does this calculator include any vendor prices?
- No, every price is your own input, so copy the current rate from your provider’s pricing page.
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