How This Calculator Works
API Cost turns the inputs into a visible formula-based estimate. Use the result as a planning check, then compare a lower, expected, and higher scenario when the input values are uncertain.
Use the API request cost calculator to estimate AI or metered API costs from request count, input units, output units, and per-million unit pricing.
The calculator multiplies request volume by average input and output units, then applies per-million pricing for each side.
Formula
Cost = input units / 1,000,000 x input price + output units / 1,000,000 x output price.
Example Calculation
100,000 requests with 750 input and 250 output units at $0.50 and $1.50 per million costs about $75.
When to Use This Calculator
- Estimate AI API bills
- Compare prompts
- Plan usage-based pricing
Practical Scenarios
- Use the calculator before a decision depends on the number, then write down the inputs that would be easiest to verify. Use case: Estimate AI API bills.
- Rerun the estimate when the most uncertain input changes, so the result shows a useful range instead of one brittle answer. Start with API Cost, then compare the changed result with the original.
- Use the related calculators when the result affects a wider cost, schedule, or planning workflow. This is especially useful when you need to plan usage-based pricing.
Tips
- Output length can dominate cost
- Add retries and background jobs
- Check provider pricing before launch
Common Mistakes
- Ignoring failed retries
- Averaging only short requests
- Forgetting logs, embeddings, or batch jobs
- Using one unusually good input as if it were the normal case.
- Mixing units, time periods, or assumptions from different scenarios.
Assumptions and Limitations
The API Request Cost Calculator is most useful when every input belongs to the same real-world scenario, unit, and time period. Review the formula, assumptions, and related calculators before using the result in a decision.
- Local rules, fees, availability, timing, and real-world conditions can change the result.
- The result is an estimate and should be checked before making an important decision.
- Use realistic low, expected, and high scenarios when uncertainty matters.
API Cost uses API cost, AI API pricing, token cost and requests as the main context for the formula, example, and assumptions.
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