Direct answer
How to Estimate API Cost for 1 Million Tokens
A direct formula for estimating LLM API spend from input and output token prices.
Question
How do you estimate API cost for 1 million tokens?
Multiply input tokens by the provider input price and output tokens by the output price, then add both costs.
Formula
cost = input_millions x input_price + output_millions x output_price
Best use
Scenario planning before deployment
Caveat
Provider invoices and current pricing are authoritative
Explanation
Most LLM APIs price input and output tokens separately.
A 1M-token scenario should specify how many tokens are input and how many are output.
Vendor pricing changes, so use this as a planning estimate and verify final billing with the provider.