Compare / head-to-head
Claude Sonnet 4.5vsGPT-5.1
GPT-5.1 leads 4 of 5 shared benchmarks. GPT-5.1 is 1.6x cheaper per token. GPT-5.1 has the larger context window (400K tokens).
Benchmarks from cited public sources; pricing from official pages; status from official provider feeds.
Shared benchmarks
1 – 4
GPT-5.1 leads
Cheaper per token
GPT-5.1
1.6x cheaper, input + output
Larger context
GPT-5.1
400K tokens
Provider uptime (30d)
100% · 95.4802%
Anthropic · OpenAI
Claude Sonnet 4.5
Anthropic · released 2025-09-29
textvision
Quality
Benchmark matrix
5 shared · 15 only Claude Sonnet 4.5 · 1 only GPT-5.1| Benchmark | Claude Sonnet 4.5 | GPT-5.1 | Δ | Edge |
|---|---|---|---|---|
| Reported by both · 5 | ||||
| GPQA Diamond | 83.4% ↗ | 87.6% ↗epoch | -4.2 pt | GPT-5.1 |
| AIME 2025 | 84.2% ↗matharena ⚠ | 94.2% ↗matharena ⚠ | -10 pt | GPT-5.1 |
| OTIS Mock AIME 2024-2025 (Epoch AI run) | 77.8% ↗epoch | 88.6% ↗epoch | -10.8 pt | GPT-5.1 |
| SimpleQA Verified | 30.7% ↗epoch | 48% ↗epoch | -17.3 pt | GPT-5.1 |
| SWE-bench Verified (Epoch AI run) | 71.3% ↗epoch | 68% ↗epoch | +3.3 pt | Claude Sonnet 4.5 |
| Only Claude Sonnet 4.5 reports · 15 | ||||
| SWE-bench Verified | 77.2% ↗ | not reported | — | — |
| Humanity's Last Exam (no tools) | 17.7% ↗ | not reported | — | — |
| ARC-AGI-2 (Verified) | 13.6% ↗ | not reported | — | — |
| FrontierMath Tier 4 v2 (Epoch AI run) | 2.4% ↗epoch | not reported | — | — |
| FrontierMath Tiers 1-3 v2 (Epoch AI run) | 23.9% ↗epoch | not reported | — | — |
| GDPval-AA | 1276 ↗ | not reported | — | — |
| Humanity's Last Exam (with tools) | 33.6% ↗ | not reported | — | — |
| MCP Atlas | 43.8% ↗ | not reported | — | — |
| MMMLU | 89.5% ↗ | not reported | — | — |
| MMMU-Pro (no tools) | 63.4% ↗ | not reported | — | — |
| MMMU-Pro (with tools) | 68.9% ↗ | not reported | — | — |
| OSWorld-Verified | 61.4% ↗ | not reported | — | — |
| Tau2-bench Retail | 86.2% ↗ | not reported | — | — |
| Tau2-bench Telecom | 98% ↗ | not reported | — | — |
| Terminal-Bench 2.0 | 51% ↗ | not reported | — | — |
| Only GPT-5.1 reports · 1 | ||||
| LMArena Elo | not reported | 1422.6 ↗ | — | — |
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 Sonnet 4.5 minus GPT-5.1 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 Sonnet 4.5 | GPT-5.1 | Edge |
|---|---|---|---|
| Context window | 200K tokens | 400K tokens | GPT-5.1 |
| Max output | 64K tokens | 128K tokens | GPT-5.1 |
| Input price / 1M | $3 ↗ | $1.25 ↗ | GPT-5.1 |
| Output price / 1M | $15 ↗ | $10 ↗ | GPT-5.1 |
| Cached input / 1M | $0.3 ↗ | $0.125 ↗ | GPT-5.1 |
| Input + output / 1M Lower is cheaper. List prices; batch, tool and regional fees excluded. | $18 | $11.25 | GPT-5.1 |
| Modalities | text · vision | text · vision | Tie |
| Released | 2025-09-29 | 2025-11-13 | — |
| Cited benchmark scores | 21 | 6 | — |
Reliability
Provider status
Last 60 days · refreshed daily on this page · live on /statusMore matchups
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Which one wins on your data?
Public benchmarks are a starting point. Run Claude Sonnet 4.5 and GPT-5.1 on your own prompts with Respan evals, or route to either through one gateway key with automatic failover.