AI model comparison
Claude Opus 5.5 vs GPT-5.6 Terra
Side by side comparison of Claude Opus 5.5 and GPT-5.6 Terra on pricing, benchmark scores, context window, and more.
Claude Opus 5.5 is Anthropic's flagship model for demanding reasoning, coding, and long-horizon agentic work, succeeding Claude Opus 5.
- Input / 1M
- $4
- Output / 1M
- $20
- Context
- 1M
GPT-5.6 Terra is a balanced model in OpenAI's GPT-5.6 series, positioned between the flagship Sol tier and the cost-efficient Luna tier.
- Input / 1M
- $2
- Output / 1M
- $12
- Context
- 1.05M
Comparing image generators? Compare image models
At a glance
Quick verdict
How the two models stack up on the things people ask about most.
Lower price
GPT-5.6 Terra
1.8x cheaper for a typical chat
Higher intelligence score
Not available
Not enough benchmark data
Larger context window
GPT-5.6 Terra
1.05M vs 1M tokens
Newer release
Claude Opus 5.5
Released September 22, 2026
Benchmarks
Benchmark scores
Independent scores from Artificial Analysis. Higher is better.
Intelligence index
Claude Opus 5.558.4GPT-5.6 TerraNot availableCoding index
Claude Opus 5.5Not availableGPT-5.6 Terra76.7Agentic index
Claude Opus 5.5Not availableGPT-5.6 Terra43.2Pricing
Claude Opus 5.5 vs GPT-5.6 Terra API pricing
Per-token API rates. Cheaper option highlighted.
| Metric | Claude Opus 5.5 | GPT-5.6 Terra |
|---|---|---|
| Input tokensPer 1M tokens | $4 | $2 |
| Output tokensPer 1M tokens | $20 | $12 |
| Cached input (read)Per 1M tokens | $0.20 | $0.20 |
| Cache writePer 1M tokens | $5 | $2.50 |
| Long-context pricingPer 1M tokens, for very long prompts | Same rate at any length | $4 in / $18 out above 272K |
| Web searchPer request | $0.01 | $0.01 |
What it costs in practice
Estimated cost per 1,000 requests at standard rates. Coding and long-document figures also show the cost when the input is already cached.
Chat message
2K in, 500 out
Claude Opus 5.5$18GPT-5.6 Terra$10Coding task
30K in, 4K out
Claude Opus 5.5$200$86 cachedGPT-5.6 Terra$108$54 cachedLong document summary
150K in, 2K out
Claude Opus 5.5$640$70 cachedGPT-5.6 Terra$324$54 cachedSpecs
Context window and capabilities
How much each model can read, how much it can write, and what it accepts as input.
| Metric | Claude Opus 5.5 | GPT-5.6 Terra |
|---|---|---|
| Context window | 1M tokens | 1.05M tokens |
| Max output | 128K tokens | 128K tokens |
| Input types | File, Image, Text | File, Image, Text |
| Output types | Text | Text |
| Reasoning effort levels | Max, Extra high, High, Medium, Low | Max, Extra high, High, Medium, Low, None |
| Default reasoning effort | High | Medium |
| Release date | September 22, 2026 | July 9, 2026 |
Features
Supported features
API features available for each model.
| Metric | Claude Opus 5.5 | GPT-5.6 Terra |
|---|---|---|
| Tool calling | Supported | Supported |
| Structured outputs | Supported | Supported |
| JSON mode | Supported | Supported |
| Reasoning | Supported | Supported |
| Temperature | Not supported | Not supported |
| Stop sequences | Supported | Not supported |
| Deterministic seed | Not supported | Supported |
| Verbosity control | Supported | Supported |
Keep exploring
More on these models
Other head-to-heads, the full model page, and the alternatives list for each model.
Claude Opus 5.5View full model details- Claude Opus 5.5 vs GPT-6 Astra
- Claude Opus 5.5 vs GPT-6.1 Sol
- Claude Opus 5.5 vs Claude Sonnet 5.5
- Claude Opus 5.5 vs GPT-6.1 Terra
- Claude Opus 5.5 vs DeepSeek V4.1 Flash 1017
- Claude Opus 5.5 vs Gemini 4 Argon
- Claude Opus 5.5 vs DeepSeek V4.1 Flash
- Claude Opus 5.5 vs Claude Fable 5.1
- Claude Opus 5.5 vs GLM 5.3 Flash
- Claude Opus 5.5 vs Kimi K3.1 Pro
- Claude Opus 5.5 vs Hy4 preview
- Claude Opus 5.5 vs Muse Spark 1.3
- Claude Opus 5.5 vs GPT-6 Luna
- Claude Opus 5.5 vs Claude Haiku 5.5
- Claude Opus 5.5 vs Grok 4.7
- Claude Opus 5.5 vs GLM 5.3
- Claude Opus 5.5 vs Step 5 Preview
- Claude Opus 5.5 vs MiMo-V2.6-Flash
- Claude Opus 5.5 vs DeepSeek V4 Flash 0731
- Claude Opus 5.5 vs Hy3
- Claude Opus 5.5 vs Kimi K3
- Claude Opus 5.5 vs GLM 5.2
- Claude Opus 5.5 vs Claude Sonnet 5
- Claude Opus 5.5 vs Claude Opus 5
- Claude Opus 5.5 vs GPT-5.6 Sol
- Claude Opus 5.5 vs GPT-6 Sol
- Claude Opus 5.5 vs Claude Sonnet 4.5
- Claude Opus 5.5 vs Claude Sonnet 4.6
- Claude Opus 5.5 vs Claude Opus 4.8
- Claude Opus 5.5 vs Claude Haiku 4.5
- Claude Opus 5.5 vs Grok 4.6
- Claude Opus 5.5 vs Muse Wonder
Our take
GPT-5.6 Terra is 1.8x cheaper for a typical chat. GPT-5.6 Terra has the larger context window (1.05M vs 1M tokens). The right pick depends on your workload, so the quickest way to settle it is to send the same prompt to both and compare.
FAQ
Frequently asked questions
Is Claude Opus 5.5 or GPT-5.6 Terra cheaper?
GPT-5.6 Terra is cheaper for a typical chat (2K input tokens and 500 output tokens). GPT-5.6 Terra costs $2 per 1M input tokens and $12 per 1M output tokens, while Claude Opus 5.5 costs $4 per 1M input tokens and $20 per 1M output tokens.
Which has a bigger context window, Claude Opus 5.5 or GPT-5.6 Terra?
GPT-5.6 Terra supports up to 1.05M tokens of context, compared with 1M for Claude Opus 5.5.
Can I use Claude Opus 5.5 and GPT-5.6 Terra at the same time?
Yes. Shortcut Chat sends one prompt to multiple models at once, so you can see Claude Opus 5.5 and GPT-5.6 Terra answer side by side and keep the better response.
Why choose? Ask both.
Send one prompt to Claude Opus 5.5 and GPT-5.6 Terra at the same time. Compare the answers side by side and keep the best one.