Claude Sonnet 5.5 vs DeepSeek-V4.1-Flash-1017
| Spec | Claude Sonnet 5.5 | DeepSeek-V4.1-Flash-1017 |
|---|---|---|
| Respan Index | 73.1 (#2) | 59.4 (#15) |
| Blended price per 1M | $2 | $0.074 |
| Context window | 1M | 1M |
| Input / output per 1M | $1 / $5 | $0.035 / $0.192 |
| Max output | 128K | - |
| Input | text, vision | text, image |
| Released | 2026-09-28 | 2026-10-17 |
Respan Index by category
Each category is scored 0 to 100, and how far ahead the winner is. Leads under a point are close to even.
| Category | Claude Sonnet 5.5 | DeepSeek-V4.1-Flash-1017 |
|---|---|---|
| Coding | 79.6 Claude Sonnet 5.5 | 47.7 DeepSeek-V4.1-Flash-1017 |
| Agents | 78.4 Claude Sonnet 5.5 | 76.8 DeepSeek-V4.1-Flash-1017 |
| Reasoning | 79.0 Claude Sonnet 5.5 | 61.5 DeepSeek-V4.1-Flash-1017 |
| Knowledge & language | 48.5 Claude Sonnet 5.5 | 42.6 DeepSeek-V4.1-Flash-1017 |
| Human preference | 60.2 Claude Sonnet 5.5 | 57.6* DeepSeek-V4.1-Flash-1017 |
* Estimated: no published scores in that category. How the Respan Index works
Benchmarks both report
Claude Sonnet 5.5 leads on 11 of the 11 benchmarks both report. Higher is better. Each score links to where it was published.
| Benchmark | Claude Sonnet 5.5 | DeepSeek-V4.1-Flash-1017 |
|---|---|---|
| Chess Puzzles (Epoch AI) | 59% | 46% |
| Humanity's Last Exam (no tools) | 56.9% | 42.6% |
| APEX-Agents (Mercor) | 75.5% | 69.8% |
| FrontierMath Tier 4 v2 (Epoch AI) | 80.5% | 46.3% |
| FrontierMath Tiers 1-3 v2 (Epoch AI) | 88.8% | 71.2% |
| GPQA Diamond | 95.6% | 93.2% |
| Mystery Game Puzzles (Epoch AI) | 65% | 49% |
| OTIS Mock AIME 2024-2025 (Epoch AI) | 100% | 99.4% |
| SimpleQA Verified | 46.5% | 42.5% |
| Terminal-Bench 4.0 (Vals AI) | 64.1% | 31.8% |
| Terminal-Bench 4.0 | 70.6% | 42.3% |
FAQ
Is Claude Sonnet 5.5 better than DeepSeek-V4.1-Flash-1017?
Claude Sonnet 5.5 scores 73.1 on the Respan Index (#2), ahead of DeepSeek-V4.1-Flash-1017 at 59.4 (#15). Claude Sonnet 5.5 leads on 11 of the 11 benchmarks both report.
Which is cheaper, Claude Sonnet 5.5 or DeepSeek-V4.1-Flash-1017?
Claude Sonnet 5.5 lists at $1 input and $5 output per 1M tokens; DeepSeek-V4.1-Flash-1017 at $0.035 and $0.192. DeepSeek-V4.1-Flash-1017 is 27x cheaper per token at list price.
Which has the larger context window?
Both accept 1M tokens of context.
Compare other models
- vsClaude Sonnet 5.5 vs Gemini 3.8 Flash
- vsClaude Sonnet 5.5 vs Grok 4.7
- vsClaude Sonnet 5.5 vs Claude Opus 5.5
- vsClaude Sonnet 5.5 vs GPT-6 Astra
- vsClaude Sonnet 5.5 vs Kimi K3.1 Pro
- vsDeepSeek-V4.1-Flash-1017 vs Muse Wonder
- vsDeepSeek-V4.1-Flash-1017 vs Claude Haiku 5.5
- vsDeepSeek-V4.1-Flash-1017 vs GPT-5.6 Sol