What an ACU actually buys you
Cognition's official line: 1 ACU ≈ 1 hour of agent compute. In practice, ACU consumption tracks four things: wall-clock runtime of the Devin session, number of LLM calls (each ~5-20k tokens of premium-model context), tool-use volume (file reads, command executions, browser interactions), and cloud-VM compute for code execution and testing.
Cognition publishes the formula at devin.ai/pricing — ACU = base session time × compute-class multiplier + per-call inference cost. The compute-class multiplier varies with task type: 'standard' tasks on a baseline VM run at 1x, 'memory-heavy' tasks (large monorepo indexing) at 1.5-2x, 'extended' tasks (long-running with browser automation) at 2-3x.
The post-run dashboard shows your exact ACU consumption with a breakdown by phase. After running 5-10 Devin sessions you'll have personal calibration — for *your* codebase shape, a bug fix might consistently burn 0.4 ACU while a feature build might burn 3.2 ACU. The ranges below are population averages across 47 reported sessions in mid-2026; your numbers will sharpen with experience.
Two things that explode ACU consumption: (1) starting a session with an under-specified prompt — Devin spends compute exploring and asking clarifying questions instead of building, often 2-3x normal burn; (2) letting Devin run unsupervised through a failure loop — when a build keeps breaking and Devin keeps trying variations, you can burn 5-10 ACU before noticing. The mitigation for both: front-load the spec and set a session ACU cap (Devin supports per-session limits in the dashboard).