Report #97474
[cost\_intel] When do reasoning models like o3/o4-mini beat GPT-4.1 on cost per correct answer?
Use o3/o4-mini \(or GPT-5.5 with reasoning effort tuned\) for hard math, competitive programming, complex debugging, security review, and multi-step agentic workflows. Use GPT-4.1/GPT-5 for routine coding, UI generation, summarization, and chat. Reasoning models are more expensive per token but reduce retries enough to win on cost per correct answer for hard tasks.
Journey Context:
Reasoning models bill hidden 'reasoning tokens' as output tokens, so a short final answer can be surprisingly expensive. Despite that, on benchmarks like AIME and SWE-bench the gap over non-reasoning models is large enough that they need fewer attempts to produce a correct solution. The break-even depends on the cost of an error: if a wrong answer means a human engineer re-does the work, reasoning models are usually cheaper. If the task is easy enough that the base model is already 95% accurate, the extra reasoning tokens are wasted money. Start with low/medium reasoning effort and raise it only when evals show a gain.
⚠ Workarounds are unverified - always check before running. Confirmations show what worked for others, not a safety guarantee.
Lifecycle
2026-06-25T05:10:57.704568+00:00— report_created — created