Claude Opus 4.8 vs GPT-5.5
Anthropic's flagship against OpenAI's flagship — published pricing, context windows and specs, side by side.
Claude Opus 4.8 vs GPT-5.5: side-by-side
| Claude Opus 4.8 | GPT-5.5 | |
|---|---|---|
| Maker | Anthropic | OpenAI |
| Released | 27 May 2026 | 23 April 2026 |
| Tier | Flagship | Flagship |
| Context window | 1,000,000 tokens | 1,000,000 tokens (400K in Codex CLI) |
| Max output | Up to 128,000 tokens | Not specified |
| API price (per 1M) | $5 / $25 per 1M tokens | $5 / $30 per 1M tokens (Thinking) |
| Access | Proprietary — Claude API & claude.ai | Proprietary — ChatGPT & Codex (Plus, Pro, Business, Enterprise) + API |
| Best at | Long-horizon agentic work, coding, knowledge work | Agentic coding, computer use, deep research |
| Standout | Current Opus flagship — same $5/$25 rate card as Opus 4.7, adaptive thinking, controllable effort levels | First full retrain since GPT-4.5 — unified multimodal (text, images, audio, video) |
Price comparison
| Model | Input (per 1M) | Output (per 1M) |
|---|---|---|
| Claude Opus 4.8 | $5.00 | $25.00 |
| Claude Opus 4.8 (fast mode) | $10.00 | $50.00 |
| GPT-5.5 (Thinking) | $5.00 | $30.00 |
| GPT-5.5 Pro | $30.00 | $180.00 |
Estimate your monthly API cost for Claude Opus 4.8 vs GPT-5.5 with the LLM API pricing calculator →
Published benchmark figures
Each figure below is the model's own published score as listed on its AI Model Hub page. Different suites (and suite versions) are not directly comparable.
| Model | Benchmark | Published score |
|---|---|---|
| GPT-5.5 | Terminal-Bench 2.0 | 82.7% |
| GPT-5.5 | GDPval | 84.9% |
| GPT-5.5 | Expert-SWE | 73.1% |
| GPT-5.5 | SWE-bench Pro | 58.6% |
| GPT-5.5 | FrontierMath Tier 4 | 35.4% |
What the table says
- Pricing. Claude Opus 4.8 lists at $5 / $25 per 1M tokens; GPT-5.5 lists at $5 / $30 per 1M tokens (Thinking). On these published rates, Claude Opus 4.8's input price is 1x lower than GPT-5.5's, and Claude Opus 4.8's output price is 1.2x lower than GPT-5.5's. Claude Opus 4.8 also offers a fast mode at $10 / $50 per 1M tokens with up to 2.5x output speed. GPT-5.5 Pro lists at $30 / $180 per 1M tokens.
- Context. Both are in the same context class: Claude Opus 4.8 lists 1,000,000 tokens and GPT-5.5 lists 1,000,000 tokens (400K in Codex CLI).
- Access. Both are proprietary, hosted-API models; neither publishes weights for self-hosting.
- Benchmarks. The two model pages report results on different benchmark suites, so the published scores are not directly comparable head-to-head; the tables below list each model's own published figures.
Key takeaway
Everything above is drawn from the two models' published rate cards and spec sheets. Which one fits depends on the workload you price it against — run your own token volumes through the pricing calculator to see the monthly difference.
Full Claude Opus 4.8 overview Full GPT-5.5 overview
Frequently asked questions
Which is cheaper, Claude Opus 4.8 or GPT-5.5?
Claude Opus 4.8 — it lists at $5 / $25 per 1M tokens versus $5 / $30 per 1M tokens (Thinking) for GPT-5.5.
Which has the bigger context window, Claude Opus 4.8 or GPT-5.5?
They are in the same class: Claude Opus 4.8 lists 1,000,000 tokens and GPT-5.5 lists 1,000,000 tokens (400K in Codex CLI).
Which model is newer?
Claude Opus 4.8 is the more recent release (27 May 2026); GPT-5.5 was released 23 April 2026.
Can I run Claude Opus 4.8 or GPT-5.5 locally?
No — both Claude Opus 4.8 and GPT-5.5 are proprietary models accessed through their vendors' APIs and apps; neither publishes weights.
Related comparisons
- Claude Sonnet 5 vs GPT-5.5 →
- Claude Fable 5 vs Claude Opus 4.8 →
- Claude Opus 4.8 vs Claude Opus 4.7 →
- GPT-5.5 vs Gemini 3.1 →