LLM Comparison
Claude Sonnet 5.5 vs GPT-5.6 Terra
Side-by-side specs, pricing & capabilities · Updated September 2026
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2/6 models| Organization | ||
| OpenTools Score | 71 10.2 | |
| Family | Claude Sonnet | GPT-5.6 |
| Status | Current | Current |
| Release Date | Sep 2026 | Jul 2026 |
| Context Window | 1.0M tokens | 1.1M tokens |
| Input Price | $2.00/M tokens | $2.00/M tokens |
| Output Price | $10.00/M tokens | $12.00/M tokens |
| Pricing Notes | Anthropic Claude API standard tier, USD per million tokens: $2 input, $10 output; 5-minute cache writes $2.50, 1-hour cache writes $4, cache reads $0.20. Batch API gives 50% off input and output. A 300K output limit is available only for Message Batches API with the output-300k-2026-03-24 beta header; standard maximum output is 128K. Provider and regional terms may vary. | OpenAI pricing page lists $2.50 input and $15 output per 1M tokens, with GPT-5.6 cache-write and cache-read pricing. |
| Capabilities | textvisionreasoningcodingtool-uselong-contextcontext-caching | textvisionreasoningcodingtool-useweb-searchfile-searchcomputer-useagents |
| Training Cutoff | 2026-06 | Feb 16, 2026 |
| Max Output | 128K tokens | 128K tokens |
| API Identifier | claude-sonnet-5-5 | gpt-5.6-terra |
| Benchmarks | ||
| Artificial Analysis Intelligence Index v4.3.2 | 55.9779549012591artificial-analysis | — |
| Artificial Analysis Intelligence Index | — | 55artificial-analysis |
| Artificial Analysis Coding Agent Index | — | 77.4artificial-analysis |
| Artificial Analysis Intelligence Index v4.3 | — | 42.2515artificial-analysis |
| GPQA Diamond | — | 92.5253artificial-analysis |
| SciCode | — | 54.9769artificial-analysis |
| Terminal-Bench 2.1 | — | 88.015artificial-analysis |
| View Claude Sonnet 5.5 | View GPT-5.6 Terra | |
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| Model | Input | Output | Total / mo | vs Best |
|---|---|---|---|---|
| Claude Sonnet 5.5Cheapest | $2.00 | $5.00 | $7.00 | — |
| GPT-5.6 Terra | $2.00 | $6.00 | $8.00 | +14% |
Anthropic
Claude Sonnet 5.5
Claude Sonnet 5.5 is Anthropic's proprietary adaptive-reasoning model. The Claude API identifier is claude-sonnet-5-5. It accepts text and images, returns text, has a 1,000,000-token context window and a 128,000-token standard output limit. Anthropic lists standard API input and output pricing at $2 and $10 per million tokens.
OpenAI
GPT-5.6 Terra
GPT-5.6 Terra is OpenAI balanced GPT-5.6 model for teams that need strong reasoning and agentic performance at lower cost than Sol. OpenAI model docs list a 1.05M token context window, 128K max output, and support for functions, web search, file search, and computer use.
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