How to estimate API usage cost
AI API cost is generally estimated from input token cost plus output token cost, then scaled by request volume and billing period. Input and output prices may differ, and both model choice and usage change project or monthly spend.
Formula: Estimated API cost = input tokens × input price + output tokens × output price.
Illustrative example: If one request uses 1,000 input tokens and 500 output tokens, 10,000 similar requests use 10M input tokens and 5M output tokens. The actual amount depends on the selected model’s current input and output pricing.
Use the calculator above to choose a model, enter usage, and estimate project or monthly API spend.
Launch budgeting
Set a monthly API cost range for support, RAG, or agent features.
Model option comparison
Compare model choices and input/output ratios at the same call volume.
Usage growth planning
See when a changing daily call volume requires a budget adjustment.