Reasoning Token Ratio
Definition
Measure cost per output token to help correlate efficiency changes with cost-per-thought movements. Reasoning tokens are often billed at a premium. A rising ratio means cost per output token increases even if volume stays flat signaling an optimization opportunity for FinOps Practitioner and Engineering Personas .
Formula, as published
Reasoning Ratio = Reasoning Output Tokens / Total Output Tokens x 100
Calculate it
Example values to start with; replace them with yours.
From the FinOps Foundation
More Usage Optimization KPIs
Definition and formula: Reasoning Token Ratio, FinOps KPI library, FinOps Foundation, licensed CC BY 4.0, read 16 Oct 2026. Changed: HTML removed, dashes and British spellings changed, formula split from its data sources and examples. The calculator and the notes are Finitizer’s.
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