Compare / head-to-head
Claude Opus 4.8vsClaude Sonnet 5.5
Claude Sonnet 5.5 leads 19 of 23 shared benchmarks. Claude Sonnet 5.5 is 2.5x 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
4 – 19
Claude Sonnet 5.5 leads
Cheaper per token
Claude Sonnet 5.5
2.5x cheaper, input + output
Larger context
Tie
both 1M tokens
Providers
Anthropic
same provider
Claude Opus 4.8
Anthropic · released 2026-05-28
textvision
Claude Sonnet 5.5
Anthropic · released 2026-09-28
textvision
Quality
Benchmark matrix
23 shared · 17 only Claude Opus 4.8 · 6 only Claude Sonnet 5.5| Benchmark | Claude Opus 4.8 | Claude Sonnet 5.5 | Δ | Edge |
|---|---|---|---|---|
| Reported by both · 23 | ||||
| GPQA Diamond | 93.6% ↗ | 95.6% ↗epoch run | -2 pt | Claude Sonnet 5.5 |
| LMArena Elo | 1452.7 ↗ | 1471 ↗ | -18.3 | Claude Sonnet 5.5 |
| APEX-Agents (Mercor) | 48.9% ↗ | 75.5% ↗ | -26.6 pt | Claude Sonnet 5.5 |
| FrontierMath Tier 4 v2 (Epoch AI run) | 56.1% ↗epoch run | 80.5% ↗epoch run | -24.4 pt | Claude Sonnet 5.5 |
| FrontierMath Tiers 1-3 v2 (Epoch AI run) | 80% ↗epoch run | 88.8% ↗epoch run | -8.8 pt | Claude Sonnet 5.5 |
| Furniture Assembly (Epoch AI run) | 42.5% ↗epoch run | 75% ↗epoch run | -32.5 pt | Claude Sonnet 5.5 |
| Humanity's Last Exam (with tools) | 57.9% ↗ | 64.5% ↗ | -6.6 pt | Claude Sonnet 5.5 |
| LiveBench Agentic Coding (LiveBench) | 50.5% ↗ | 56.3% ↗ | -5.8 pt | Claude Sonnet 5.5 |
| LiveBench Coding (LiveBench) | 81.8% ↗ | 91.4% ↗ | -9.6 pt | Claude Sonnet 5.5 |
| LiveBench Data Analysis (LiveBench) | 66% ↗ | 78.6% ↗ | -12.6 pt | Claude Sonnet 5.5 |
| LiveBench Instruction Following (LiveBench) | 72% ↗ | 70.5% ↗ | +1.5 pt | Claude Opus 4.8 |
| LiveBench Language (LiveBench) | 79.7% ↗ | 83.4% ↗ | -3.7 pt | Claude Sonnet 5.5 |
| LiveBench Mathematics (LiveBench) | 94.3% ↗ | 96.7% ↗ | -2.4 pt | Claude Sonnet 5.5 |
| LiveBench Reasoning (LiveBench) | 89.2% ↗ | 91.6% ↗ | -2.4 pt | Claude Sonnet 5.5 |
| LMArena Agent (LMArena) | 0.0664 ↗ | 0.1252 ↗ | -0.1 | Claude Sonnet 5.5 |
| LMArena Vision (LMArena) | 1286.4 ↗ | 1268.3 ↗ | +18.1 | Claude Opus 4.8 |
| LMArena WebDev (LMArena) | 1555.5 ↗ | 1786.3 ↗ | -230.8 | Claude Sonnet 5.5 |
| Mystery Game Puzzles (Epoch AI run) | 36% ↗epoch run | 65% ↗epoch run | -29 pt | Claude Sonnet 5.5 |
| OTIS Mock AIME 2024-2025 (Epoch AI run) | 98.3% ↗epoch run | 100% ↗epoch run | -1.7 pt | Claude Sonnet 5.5 |
| SAGE (Vals AI) | 54.8% ↗ | 51.8% ↗ | +3 pt | Claude Opus 4.8 |
| SimpleBench (SimpleBench) | 64.8% ↗ | 75.9% ↗ | -11.1 pt | Claude Sonnet 5.5 |
| SimpleQA Verified | 53% ↗epoch run | 46.5% ↗epoch run | +6.5 pt | Claude Opus 4.8 |
| Terminal-Bench 4.0 (Vals AI) | 23.2% ↗ | 64.1% ↗ | -40.9 pt | Claude Sonnet 5.5 |
| Only Claude Opus 4.8 reports · 17 | ||||
| SWE-bench Verified | 88.6% ↗ | not reported | — | — |
| AIME 2026 | 100% ↗matharena ⚠ | not reported | — | — |
| Humanity's Last Exam (no tools) | 49.8% ↗ | not reported | — | — |
| BrowseComp | 84.3% ↗ | not reported | — | — |
| Chess Puzzles (Epoch AI run) | 34% ↗epoch run | not reported | — | — |
| DeepSWE v1.1 (Datacurve) | 59% ↗ | not reported | — | — |
| EBR-bench (Epoch AI run) | 28.6% ↗epoch run | not reported | — | — |
| GSO Opt@1 (GSO) | 47.1% ↗ | not reported | — | — |
| OSWorld-Verified | 83.4% ↗ | not reported | — | — |
| SWE-bench Multilingual | 84.4% ↗ | not reported | — | — |
| SWE-bench Multimodal | 38.4% ↗ | not reported | — | — |
| SWE-Bench Pro | 69.2% ↗ | not reported | — | — |
| tau2-bench Banking Knowledge (Sierra) | 39.7% ↗ | not reported | — | — |
| Terminal-Bench 2.1 | 74.6% ↗ | not reported | — | — |
| Toolathlon-Verified (HKUST) | 76.2% ↗ | not reported | — | — |
| Vending-Bench 2 (Andon Labs) | 5787.43 ↗ | not reported | — | — |
| WeirdML (Håvard Tveit Ihle) | 82.9% ↗ | not reported | — | — |
| Only Claude Sonnet 5.5 reports · 6 | ||||
| Chartography (no tools) | not reported | 61.6% ↗ | — | — |
| CursorBench 4.0 | not reported | 55.5% ↗ | — | — |
| FrontierCode v1.1 (Main) | not reported | 46.2% ↗ | — | — |
| FrontierSWE V2 (Proximal Labs) | not reported | 61.9% ↗ | — | — |
| OSWorld 2.1 (partial) | not reported | 80.1% ↗ | — | — |
| Terminal-Bench 4.0 | not reported | 70.6% ↗ | — | — |
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 4.8 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 4.8 | Claude Sonnet 5.5 | Edge |
|---|---|---|---|
| Context window | 1M tokens | 1M tokens | Tie |
| Max output | 128K tokens | 128K tokens | Tie |
| Input price / 1M | $5 ↗ | $2 ↗ | Claude Sonnet 5.5 |
| Output price / 1M | $25 ↗ | $10 ↗ | Claude Sonnet 5.5 |
| Cached input / 1M | $0.5 ↗ | $0.2 ↗ | Claude Sonnet 5.5 |
| Input + output / 1M Lower is cheaper. List prices; batch, tool and regional fees excluded. | $30 | $12 | Claude Sonnet 5.5 |
| Modalities | text · vision | text · vision | Tie |
| Released | 2026-05-28 | 2026-09-28 | — |
| Cited benchmark scores | 47 | 29 | — |
Reliability
Anthropic status
Live from /statusMore matchups
Claude Opus 4.8 vs …
Models sharing the most benchmarksMore matchups
Claude Sonnet 5.5 vs …
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Which one wins on your data?
Public benchmarks are a starting point. Run Claude Opus 4.8 and Claude Sonnet 5.5 on your own prompts with Respan evals, or route to either through one gateway key with automatic failover.