Claude Opus 5.5 vs DeepSeek-V4.1-Flash-1017
| Spec | Claude Opus 5.5 | DeepSeek-V4.1-Flash-1017 |
|---|---|---|
| Respan Index | 74.1 (#1) | 59.4 (#15) |
| Blended price per 1M | $4 | $0.074 |
| Context window | 1M | 1M |
| Input / output per 1M | $2 / $10 | $0.035 / $0.192 |
| Max output | 128K | - |
| Input | text, vision | text, image |
| Released | 2026-09-22 | 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 Opus 5.5 | DeepSeek-V4.1-Flash-1017 |
|---|---|---|
| Coding | 68.3 Claude Opus 5.5 | 47.7 DeepSeek-V4.1-Flash-1017 |
| Agents | 79.1 Claude Opus 5.5 | 76.8 DeepSeek-V4.1-Flash-1017 |
| Reasoning | 83.9 Claude Opus 5.5 | 61.5 DeepSeek-V4.1-Flash-1017 |
| Knowledge & language | 70.4 Claude Opus 5.5 | 42.6 DeepSeek-V4.1-Flash-1017 |
| Human preference | 61.4 Claude Opus 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 Opus 5.5 leads on 9 of the 10 benchmarks both report. Higher is better. Each score links to where it was published.
| Benchmark | Claude Opus 5.5 | DeepSeek-V4.1-Flash-1017 |
|---|---|---|
| Chess Puzzles (Epoch AI) | 67% | 46% |
| APEX-Agents (Mercor) | 73.5% | 69.8% |
| FrontierMath Tier 4 v2 (Epoch AI) | 95% | 46.3% |
| FrontierMath Tiers 1-3 v2 (Epoch AI) | 91.2% | 71.2% |
| GPQA Diamond | 90.6% | 93.2% |
| Mystery Game Puzzles (Epoch AI) | 71% | 49% |
| OTIS Mock AIME 2024-2025 (Epoch AI) | 100% | 99.4% |
| SimpleQA Verified | 72.2% | 42.5% |
| Terminal-Bench 4.0 (Vals AI) | 65.2% | 31.8% |
| Terminal-Bench 4.0 | 66.4% | 42.3% |
FAQ
Is Claude Opus 5.5 better than DeepSeek-V4.1-Flash-1017?
Claude Opus 5.5 scores 74.1 on the Respan Index (#1), ahead of DeepSeek-V4.1-Flash-1017 at 59.4 (#15). Claude Opus 5.5 leads on 9 of the 10 benchmarks both report.
Which is cheaper, Claude Opus 5.5 or DeepSeek-V4.1-Flash-1017?
Claude Opus 5.5 lists at $2 input and $10 output per 1M tokens; DeepSeek-V4.1-Flash-1017 at $0.035 and $0.192. DeepSeek-V4.1-Flash-1017 is 54x cheaper per token at list price.
Which has the larger context window?
Both accept 1M tokens of context.