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Quick Answer

Grok 4.5 vs Claude Opus 5: Cost Per Task (July 2026)

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The Short Answer

Grok 4.5 is ~3x cheaper per task than Claude Opus 5, and its token efficiency can widen that gap on multi-step agents. But Opus 5 leads on the hardest coding and agentic accuracy. The right answer for most teams isn’t one or the other — it’s a router.

The Cost Math

Grok 4.5Claude Opus 5
API in/out ($/MTok)$2 / $6$5 / $25
30K-in / 5K-out task~$0.09~$0.28
Context500K1M
Token efficiency~2x (fewer steps)Standard
EU availabilityNo (AI Act)Yes

On a typical 30K-input / 5K-output task, Grok 4.5 costs about $0.09 versus roughly $0.28 for Opus 5 — about 3x. On multi-step agentic runs, Grok’s efficiency (fewer steps, fewer output tokens) can push the effective gap even wider, since output tokens are where Opus 5’s $25 rate bites hardest.

Where Each Wins

  • Cheap, high-volume agents → Grok 4.5. Best when each step’s output is verified programmatically (test suites, rules engines) so occasional misses are caught cheaply. The efficiency pitch — solving tasks in ~half the steps — is the real cost lever.
  • Hardest coding + accuracy-critical agents → Claude Opus 5. Leads Anthropic’s coding benchmarks and agentic/computer-use evals, with a 1M context for large codebases. When a wrong answer is expensive, Opus 5’s accuracy pays for its higher price.

Token Efficiency Changes The Picture

Per-token price isn’t the whole story. Grok 4.5’s ~2x token efficiency means it often finishes an agentic task in fewer steps and fewer output tokens — so its cost-per-completed-task advantage over Opus 5 is usually larger than the 3x sticker gap suggests. Conversely, if Opus 5 one-shots a task that Grok retries, Opus 5 can close the gap. Benchmark on your own workload.

The Smart Play: Route

The teams getting the best of both run a router: default to Grok 4.5 for the ~80% of agentic steps that are easy and verifiable, then escalate to Claude Opus 5 on retries, low-confidence outputs, or the hardest refactors. Average cost lands near Grok’s while hard tasks still get Opus 5 accuracy. (If you’re in the EU, note Grok 4.5 isn’t available there — pair Opus 5 with Gemini 3.6 Flash or GPT-5.6 Luna as the cheap tier instead.)

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