High-volume, cost-sensitive work
Choose Claude Opus 5.5
Claude Opus 5.5 costs 29% less on a typical mix of three input tokens for every output token ($8.00 against $11.25 per million tokens).
Claude Opus 5.5 vs GPT-5.5: price, context and capabilities
Choose Claude Opus 5.5 for high-volume, cost-sensitive work, writing and code generation, reused prompts and documents (RAG, agents), the hardest reasoning tasks, the latest release and the most recent knowledge; on the other points the two are level or the data is missing.
In short
- Claude Opus 5.5 is 29% cheaper than GPT-5.5 at the headline price ($8.00 / 1M tokens vs $11.25 / 1M tokens).
- GPT-5.5 reads more per request: 1.05M tokens against 1M.
- Claude Opus 5.5 is the newer model (September 2026, against Apr 24, 2026).
Which should you choose?
Each answer below comes straight from the published prices, specifications and independent benchmark results.
Writing and code generation
Choose Claude Opus 5.5
Claude Opus 5.5 charges $20.00 per million output tokens, against $30.00 for GPT-5.5. Output dominates the bill when answers are long.
Reused prompts and documents (RAG, agents)
Choose Claude Opus 5.5
Claude Opus 5.5 charges $0.20 per million cached input tokens, against $0.50 for GPT-5.5.
Hardest reasoning tasks
Choose Claude Opus 5.5
Claude Opus 5.5 scores 57.6 on the Artificial Analysis Intelligence Index, against 38.4 for GPT-5.5.
Reasoning over long documents
Either one
They are practically level on Long-context reasoning (AA-LCR) (84.7% and 84.3%).
Latest release
Choose Claude Opus 5.5
Claude Opus 5.5 is the newer release (September 2026, against Apr 24, 2026 for GPT-5.5).
Most recent knowledge
Choose Claude Opus 5.5
Claude Opus 5.5 was trained on data up to June 2026, against December 2025 for GPT-5.5.
Monthly cost at three volumes
| Volume | Claude Opus 5.5 | GPT-5.5 | Difference |
|---|---|---|---|
| Prototype: 1M input, 250K output tokens | $9.00 | $12.50 | Claude Opus 5.5, $3.50 less |
| Production: 20M input, 5M output tokens | $180.00 | $250.00 | Claude Opus 5.5, $70.00 less |
| Scale: 500M input, 100M output tokens | $4,000 | $5,500 | Claude Opus 5.5, $1,500 less |
Standard rates, without caching or batch discounts. Volumes are per month.
Specifications side by side
| Claude Opus 5.5 | GPT-5.5 | |
|---|---|---|
| Provider | Anthropic | OpenAI |
| Category | Language models | Language models |
| Status | Generally available | Legacy |
| Headline price | $8.00 / 1M tokens | $11.25 / 1M tokens |
| Input | $4.00 / 1M tokens | $5.00 / 1M tokens |
| Output | $20.00 / 1M tokens | $30.00 / 1M tokens |
| Cached input | $0.20 / 1M tokens | $0.50 / 1M tokens |
| Context window | 1M | 1.05M |
| Max output | 128k | 128k |
| Released | September 2026 | Apr 24, 2026 |
| Knowledge cutoff | June 2026 | December 2025 |
| Licence | Proprietary | Proprietary |
| Capabilities | Vision, Reasoning, Tool calling, Structured output, Prompt caching, Batch API | Vision, Reasoning, Tool calling, Structured output, Prompt caching, Batch API |
| API model id | claude-opus-5-5 | gpt-5.5 |
Benchmarks side by side
Leader in bold.
| Benchmark | Claude Opus 5.5 | GPT-5.5 |
|---|---|---|
| Intelligence Index | 57.6 | 38.4 |
| SciCode | 66.9% | 55.8% |
| Humanity's Last Exam | 61.4% | 45.8% |
| MMMU-Pro (visual reasoning) | 87.7% | 79.9% |
| Long-context reasoning (AA-LCR) | 84.7% | 84.3% |
| Terminal-Bench Hard | No data | 60.6% |
| GPQA Diamond | No data | 93.5% |
| IFBench (instruction following) | No data | 75.9% |
| τ²-Bench (agentic tool use) | No data | 93.9% |
Independent evaluations by Artificial Analysis, run the same way for every model, at the reasoning setting shown. Percentages unless marked as an index.
Frequently asked questions
Should I choose Claude Opus 5.5 or GPT-5.5?
Choose Claude Opus 5.5 for high-volume, cost-sensitive work, writing and code generation, reused prompts and documents (RAG, agents), the hardest reasoning tasks, the latest release and the most recent knowledge; on the other points the two are level or the data is missing.
Which is cheaper, Claude Opus 5.5 or GPT-5.5?
Claude Opus 5.5 is 29% cheaper than GPT-5.5 at the headline price ($8.00 / 1M tokens vs $11.25 / 1M tokens).
Which has the larger context window, Claude Opus 5.5 or GPT-5.5?
GPT-5.5 reads more per request: 1.05M tokens against 1M.
What is the difference between Claude Opus 5.5 and GPT-5.5?
Claude Opus 5.5 is made by Anthropic and GPT-5.5 by OpenAI. Claude Opus 5.5 is 29% cheaper than GPT-5.5 at the headline price ($8.00 / 1M tokens vs $11.25 / 1M tokens). GPT-5.5 reads more per request: 1.05M tokens against 1M. Claude Opus 5.5 is the newer model (September 2026, against Apr 24, 2026).
How much do Claude Opus 5.5 and GPT-5.5 cost per month?
At 20 million input and 5 million output tokens a month, Claude Opus 5.5 costs $180.00 and GPT-5.5 costs $250.00, at standard rates.
Which is newer, Claude Opus 5.5 or GPT-5.5?
Claude Opus 5.5 was released on September 2026 and GPT-5.5 on Apr 24, 2026.