Pairwise benchmark snapshot · Aug 16, 2026
This page compares Claude Opus 4.6 (Anthropic) and GPT-5.6 Terra (OpenAI) using the latest snapshots we have as of Aug 16, 2026. On preference Elo, Claude Opus 4.6 is ahead by 26 points (1,574 vs 1,548; seed-bootstrap (Aug 1, 2026)). On SWE-bench coding, Claude Opus 4.6 resolves 75.9% versus 70.4% (seed-bootstrap (Aug 1, 2026)). GPT-5.6 Terra streams faster (128 tok/s) while GPT-5.6 Terra is the cheaper output token ($6/1M). GPT-5.6 Terra has the larger context window (1.1M tokens). Every cell below is a dated snapshot from a named public source — we do not invent missing scores, and we do not run SWE-bench ourselves.
Anthropic
Claude Opus 4.6Follow-on Opus release. Slightly behind 4.5 on official SWE-bench bash-only in the last published sweep; stronger long-horizon agent traces.
OpenAI
GPT-5.6 TerraOpenAI 5.6 mid tier. Official API $2/$12 per 1M after the Jul 30 2026 price cut.
Instant pairwise benchmark recalculation across 400+ LLMs
Category wins across intelligence, speed, and pricing efficiency.
Preference Elo, Coding proficiency, SWE-bench & LiveBench accuracy
Generation throughput and time to first token responsiveness
Cost per million tokens and max context window length
Each spoke is a skill. Farther from the center is better (0–100th percentile). Tap any dot to inspect details.
26 pts advantage
64 tok/s faster
$19.00/1M cheaper
Simulate monthly production API costs based on published $/1M tokens.
GPT-5.6 Terra is estimated to save $425.00/month ($5,100/year).
Higher SWE-bench (75.9%).
Lower output list price ($6/1M).
Lower TTFT (160 ms).
Larger window (1.1M).
Both accept images. Defaulting to the higher-Elo side (Claude Opus 4.6).
| Target Workload | Recommended Pick | Evaluation Rationale |
|---|---|---|
| Repo / coding agents | Claude Opus 4.6 | Higher SWE-bench (75.9%). |
| High-volume chat | GPT-5.6 Terra | Lower output list price ($6/1M). |
| Voice / low-latency UI | GPT-5.6 Terra | Lower TTFT (160 ms). |
| Long-document RAG | GPT-5.6 Terra | Larger window (1.1M). |
| Screenshots / vision | Claude Opus 4.6 | Both accept images. Defaulting to the higher-Elo side (Claude Opus 4.6). |
Terra is OpenAI’s Sonnet-class invoice. Use it when Sol is too expensive and Luna is too small.
Slightly behind 4.5 on one official SWE-bench sweep; stronger long-horizon traces. We keep the row for old vs URLs.
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The real PNG is generated at /compare/claude-opus-4-6-vs-gpt-5-6-terra/opengraph-image for crawlers.
Verified head-to-head card
