Head-to-head
Claude Sonnet 5.5 vs DeepSeek V4.1 Flash
As of October 26, 2026, Claude Sonnet 5.5 leads DeepSeek V4.1 Flash on the Analyzer Index, 84.2 to 81.5.
Normalized scores are min-maxed per benchmark across all models we track (0–100). Open the interactive compare view to add benchmarks to the radar chart or pull in more models.
Claude Sonnet 5.5
AnthropicDeepSeek V4.1 Flash
DeepSeek| At a glance | Claude Sonnet 5.5 | DeepSeek V4.1 Flash |
|---|---|---|
| Analyzer Index | 84.2 (6/13) | 81.5 (6/13) |
| Blended price | $4.00/M | $0.27/M |
| Cheapest host | maker's API | $0.11/M |
| Context | 1.0M | 1.0M |
| Output speed | 101 tok/s | 137 tok/s |
| Time to first token | 1.06 s | 1.04 s |
| Benchmark | Claude Sonnet 5.5 | DeepSeek V4.1 Flash |
|---|---|---|
Chatbot Arena Elo Arena | ||
Output Speed Speed | ||
Time to First Token TTFT | ||
Rolling Contamination-Controlled Average Rolling Avg | ||
Rolling Data Analysis Data Analysis | ||
SimpleQA Verified SimpleQA | ||
OTIS Mock AIME 2024-2025 OTIS AIME | ||
Humanity's Last Exam HLE | — | |
ARC-AGI 2 ARC-AGI 2 | — | |
Frontier Composite Frontier | ||
Output Stability Stability | — | |
Format Adherence Format | — | |
Recovery Rate Recovery | — | |
API Success Rate API OK | ||
Safety Handling Safety | — |
Methodology matches the main AI Model Analyzer About page.