Formula
Input tokens = queries × items/query × tokens/item + overhead. Unused context = context limit − reserved output − input tokens.
Values are combined without early rounding; displayed results are rounded for readability.
What the result means
The result converts the entered prompt caching workload into an operational estimate. It is most useful for scenario comparison and identifying which assumption has the largest effect.
Planning estimate only. Validate the result with load tests, provider limits, production telemetry, and a separate reliability reserve.