TL;DR — same $5 input, but Opus 5's output is 17% cheaper ($25 vs $30) — the closest head-to-head at the frontier. Every number below is from our weekly-verified pricing tracker (verified 2026-08-26).
Pricing side by side (per 1M tokens, USD)
| Model | Provider | Input | Output | |-------|----------|-------|--------| | Claude Opus 5 | Anthropic | $5 | $25 | | GPT-5.5 | OpenAI | $5 | $30 |
Verified 2026-08-26 against official rate cards — the tracker keeps the change log.
What a real month costs
At a standard workload of 10M input + 2M output tokens/month:
- Claude Opus 5: $100.00
- GPT-5.5: $110.00
On this mix, Claude Opus 5 is the cheaper column (1.1× gap). Your ratio will differ — run your own mix through the LLM cost calculator.
Choose Claude Opus 5 if
your stack leans on agentic/coding work and long generations — the $5-per-1M output gap compounds, and Anthropic's ~90% cache discount plus −50% batch API stack on top.
Choose GPT-5.5 if
your tooling, evals, or feature needs sit in OpenAI's ecosystem — at this price proximity, integration fit is a legitimate tiebreaker.
Routing decision card
- With input identical, output share decides the bill: generation-heavy traffic tilts to Opus 5
- This pair is the classic A/B: route by measured per-task quality on your own evals, not by list price
- Both are escalation tiers — the bigger win is usually routing less traffic to either
- The router answer: most teams shouldn't hard-pick one — ClawRouters routes each request to whichever side fits it, so the comparison becomes a per-call decision instead of a bet.
Per-model detail: Claude Opus 5 deep dive
Part of the LLM model comparison index. Prices move fast in 2026 — the tracker logs every change with dates.