Compare / head-to-head
Claude Sonnet 4.5vsDeepSeek V4.1 Flash
DeepSeek V4.1 Flash leads 1 of 1 shared benchmark. DeepSeek V4.1 Flash is 42.9x cheaper per token. DeepSeek V4.1 Flash has the larger context window (1M tokens).
Benchmarks from cited public sources; pricing from official pages; status from official provider feeds.
Shared benchmarks
0 – 1
DeepSeek V4.1 Flash leads
Cheaper per token
DeepSeek V4.1 Flash
42.9x cheaper, input + output
Larger context
DeepSeek V4.1 Flash
1M tokens
Provider uptime (30d)
100% · 100%
Anthropic · DeepSeek
Claude Sonnet 4.5
Anthropic · released 2025-09-29
textvision
DeepSeek V4.1 Flash
DeepSeek · released 2026-09-10
textvision
Quality
Benchmark matrix
1 shared · 19 only Claude Sonnet 4.5 · 2 only DeepSeek V4.1 Flash| Benchmark | Claude Sonnet 4.5 | DeepSeek V4.1 Flash | Δ | Edge |
|---|---|---|---|---|
| Reported by both · 1 | ||||
| GPQA Diamond | 83.4% ↗ | 90.9% ↗ | -7.5 pt | DeepSeek V4.1 Flash |
| Only Claude Sonnet 4.5 reports · 19 | ||||
| SWE-bench Verified | 77.2% ↗ | not reported | — | — |
| AIME 2025 | 84.2% ↗matharena ⚠ | 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 | — | — |
| OTIS Mock AIME 2024-2025 (Epoch AI run) | 77.8% ↗epoch | not reported | — | — |
| SimpleQA Verified | 30.7% ↗epoch | not reported | — | — |
| SWE-bench Verified (Epoch AI run) | 71.3% ↗epoch | not reported | — | — |
| Tau2-bench Retail | 86.2% ↗ | not reported | — | — |
| Tau2-bench Telecom | 98% ↗ | not reported | — | — |
| Terminal-Bench 2.0 | 51% ↗ | not reported | — | — |
| Only DeepSeek V4.1 Flash reports · 2 | ||||
| DeepSWE v1.1 | not reported | 74.2% ↗ | — | — |
| Terminal-Bench 2.1 | not reported | 90.6% ↗ | — | — |
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 DeepSeek V4.1 Flash 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 | DeepSeek V4.1 Flash | Edge |
|---|---|---|---|
| Context window | 200K tokens | 1M tokens | DeepSeek V4.1 Flash |
| Max output | 64K tokens | 384K tokens | DeepSeek V4.1 Flash |
| Input price / 1M | $3 ↗ | $0.14 ↗ | DeepSeek V4.1 Flash |
| Output price / 1M | $15 ↗ | $0.28 ↗ | DeepSeek V4.1 Flash |
| Cached input / 1M | $0.3 ↗ | $0.003 ↗ | DeepSeek V4.1 Flash |
| Input + output / 1M Lower is cheaper. List prices; batch, tool and regional fees excluded. | $18 | $0.42 | DeepSeek V4.1 Flash |
| Modalities | text · vision | text · vision | Tie |
| Released | 2025-09-29 | 2026-09-10 | — |
| Cited benchmark scores | 21 | 3 | — |
Reliability
Provider status
Last 60 days · refreshed daily on this page · live on /statusMore matchups
Claude Sonnet 4.5 vs …
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DeepSeek V4.1 Flash vs …
Models sharing the most benchmarksBuilt by Respan
Which one wins on your data?
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