text model comparison
Claude Sonnet 5.5 vs GPT-5.6 Terra
Claude Sonnet 5.5 and GPT-5.6 Terra are both current text models, from Anthropic and OpenAI. Both cost $2 per 1M input tokens. On Arena Text, Claude Sonnet 5.5 scores 1476 Elo and GPT-5.6 Terra 1466 Elo (Arena, measured October 8, 2026). GPT-5.6 Terra has the larger context window, 1,050,000 vs 1,000,000 tokens.
Data verified October 12, 2026 · Dataset 2026-10-12
Side by side
Standard-tier prices in effect today. The better value in each row is highlighted.
| Fact | Claude Sonnet 5.5 | GPT-5.6 Terra |
|---|---|---|
| Price per 1M input tokens | $2 | $2 |
| Price per 1M output tokens | $10 (better) | $12 |
| Cost of 10M input and 2M output tokens | $40 (better) | $44 |
| Arena Text | 1476 Elo (#17 of 39) (better) | 1466 Elo (#23 of 39) |
| GPQA Diamond | 95.6% (#2 of 37) (better) | 93.3% (#13 of 37) |
| FrontierMath Tiers 1-3 (v2) | 88.8% (#7 of 37) (better) | 86% (#9 of 37) |
| SimpleQA Verified | 46.5% (#21 of 34) (better) | 43.2% (#24 of 34) |
| Provider | Anthropic | OpenAI |
| Release date | September 28, 2026 | July 9, 2026 |
| Access | API only | API only |
| Context window | 1,000,000 tokens | 1,050,000 tokens |
| Max output | 128,000 tokens | 128,000 tokens |
| Input | text, image | text, image |
| Output | text | text |
When to choose each
Claude Sonnet 5.5
Best for
- Production workloads that need frontier-adjacent quality at a mid-tier rate
- Latency-sensitive agent steps inside a larger pipeline
Watch out for
- Same list price as Claude Sonnet 5, so the gain is capability and cache economics rather than a cheaper rate card
- Anthropic positions Opus 5.5 rather than this as the default, so reach for Sonnet 5.5 when latency matters more than peak capability
GPT-5.6 Terra
Best for
- Balanced long-context API evaluations
- Reasoning-heavy work that does not depend on broad factual recall
Watch out for
- Not in the pinned LiveBench snapshot; its independent scores here come from Epoch AI's own GPQA Diamond, FrontierMath and SimpleQA Verified runs
Claude Sonnet 5.5 vs GPT-5.6 Terra FAQ
Which is cheaper, Claude Sonnet 5.5 or GPT-5.6 Terra?
Both cost $2 per 1M input tokens. For 10M input and 2M output tokens, Claude Sonnet 5.5 costs $40 and GPT-5.6 Terra $44 at standard rates.
Which scores higher on independent benchmarks, Claude Sonnet 5.5 or GPT-5.6 Terra?
Claude Sonnet 5.5 leads on Arena Text, 1476 Elo to 1466 Elo; Claude Sonnet 5.5 leads on GPQA Diamond, 95.6% to 93.3%; Claude Sonnet 5.5 leads on FrontierMath Tiers 1-3 (v2), 88.8% to 86%. Scores are independent evaluations, not either vendor's launch figures.
Which has the larger context window, Claude Sonnet 5.5 or GPT-5.6 Terra?
GPT-5.6 Terra has the larger context window, 1,050,000 vs 1,000,000 tokens.
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- Claude Sonnet 5.5 vs Grok 4.6
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- Claude Sonnet 5.5 vs Qwen3.8-Max
- Claude Sonnet 5 vs Claude Sonnet 5.5
Production evaluation
Choosing between Claude Sonnet 5.5 and GPT-5.6 Terra?
Public benchmarks narrow the shortlist. We run both on your own tasks, data and cost limits, then build the routing and review controls to run the winner in production.
- A head-to-head evaluation on your real workload
- Routing between models by cost and difficulty