Compare / head-to-head
Claude Opus 5.5vsClaude Sonnet 5.5
Claude Opus 5.5 leads 3 of 4 shared benchmarks. Claude Sonnet 5.5 is 2x cheaper per token. Both offer a 1M-token context window.
Benchmarks from cited public sources; pricing from official pages; status from official provider feeds.
Shared benchmarks
3 – 1
Claude Opus 5.5 leads
Cheaper per token
Claude Sonnet 5.5
2x cheaper, input + output
Larger context
Tie
both 1M tokens
Providers
Anthropic
same provider
Claude Opus 5.5
Anthropic · released 2026-09-22
textvision
Claude Sonnet 5.5
Anthropic · released 2026-09-28
textvision
Quality
Benchmark matrix
4 shared · 5 only Claude Opus 5.5 · 2 only Claude Sonnet 5.5| Benchmark | Claude Opus 5.5 | Claude Sonnet 5.5 | Δ | Edge |
|---|---|---|---|---|
| Reported by both · 4 | ||||
| CursorBench 4.0 | 57.8% ↗ | 55.5% ↗ | +2.3 pt | Claude Opus 5.5 |
| FrontierCode v1.1 (Main) | 54.4% ↗ | 46.2% ↗ | +8.2 pt | Claude Opus 5.5 |
| Humanity's Last Exam (with tools) | 67.7% ↗ | 64.5% ↗ | +3.2 pt | Claude Opus 5.5 |
| Terminal-Bench 4.0 | 66.4% ↗ | 70.6% ↗ | -4.2 pt | Claude Sonnet 5.5 |
| Only Claude Opus 5.5 reports · 5 | ||||
| AutomationBench 1.0.6 | 40% ↗ | not reported | — | — |
| Chartography (with tools) | 89% ↗ | not reported | — | — |
| GDPval-AA v2.1 | 1846 ↗ | not reported | — | — |
| OSWorld 2.0 (partial) | 81.8% ↗ | not reported | — | — |
| Terminal-Bench Science 0.1 | 58.7% ↗ | not reported | — | — |
| Only Claude Sonnet 5.5 reports · 2 | ||||
| Chartography (no tools) | not reported | 61.6% ↗ | — | — |
| OSWorld 2.1 (partial) | not reported | 80.1% ↗ | — | — |
Scores tagged "epoch" or "matharena" are independent runs, used only where the lab has not published its own; ⚠ marks rows MathArena flags as released after the competition. Higher is better on every row. Δ is Claude Opus 5.5 minus Claude Sonnet 5.5 in the benchmark's own unit. "Not reported" means the lab has not published that figure; it is not a zero. ↗ opens the source.
Specs & pricing
Side by side
Official pricing pages and model cards| Spec | Claude Opus 5.5 | Claude Sonnet 5.5 | Edge |
|---|---|---|---|
| Context window | 1M tokens | 1M tokens | Tie |
| Max output | 128K tokens | 128K tokens | Tie |
| Input price / 1M | $4 ↗ | $2 ↗ | Claude Sonnet 5.5 |
| Output price / 1M | $20 ↗ | $10 ↗ | Claude Sonnet 5.5 |
| Cached input / 1M | $0.2 ↗ | $0.2 ↗ | Tie |
| Input + output / 1M Lower is cheaper. List prices; batch, tool and regional fees excluded. | $24 | $12 | Claude Sonnet 5.5 |
| Modalities | text · vision | text · vision | Tie |
| Released | 2026-09-22 | 2026-09-28 | — |
| Cited benchmark scores | 9 | 6 | — |
Reliability
Anthropic status
Live from /statusMore matchups
Claude Opus 5.5 vs …
Models sharing the most benchmarksMore matchups
Claude Sonnet 5.5 vs …
Models sharing the most benchmarksBuilt by Respan
Which one wins on your data?
Public benchmarks are a starting point. Run Claude Opus 5.5 and Claude Sonnet 5.5 on your own prompts with Respan evals, or route to either through one gateway key with automatic failover.