Claude Opus 5.5 vs DeepSeek V4.1 Flash
Claude Opus 5.5 (Anthropic) and DeepSeek V4.1 Flash (DeepSeek) compared on benchmarks, pricing, context window, and use-case rankings.
- Claude Opus 5.5 leads on overall intelligence (ECI 167 vs 156).
- DeepSeek V4.1 Flash is cheaper on input tokens: $0.14 vs $4.00 per 1M.
- Claude Opus 5.5 ranks higher for coding (100th vs 75th percentile).
| Attribute | Claude Opus 5.5 | DeepSeek V4.1 Flash |
|---|---|---|
| Scores | ||
| Intelligence (ECI) | 167 | 156 |
| Coding | 100 | 75 |
| Math | 88 | 74 |
| Reasoning & Knowledge | 90 | 61 |
| Agentic & Tools | 97 | 47 |
| Specifications | ||
| Developer | Anthropic | DeepSeek |
| Family | Claude | DeepSeek |
| Released | Sep 22, 2026 | Sep 9, 2026 |
| Parameters | — | 748B |
| Availability | API access | Open weights (unrestricted) |
| Context window | 1M | 1M |
| Price — $/M input | $4.00 | $0.14 |
| Price — $/M output | $20.00 | $0.54 |
| Inputs | text, image, file | text, image |
| Outputs | text | text |
| Benchmarks | ||
| AIME 2024/2025 | 100% | 98% |
| APEX | 74% | 40% |
| ARC-AGI | 99% | 95% |
| ARC-AGI-2 | 93% | 73% |
| GPQA Diamond | 91% | 90% |
| Humanity's Last Exam | 61% | 39% |
| SciCode | 67% | 52% |
| SimpleQA Verified | 72% | 43% |
| WebDev Arena | 1820 | 1614 |
Use-case scores are 0–100 percentile composites across each area’s benchmarks, ranked against every model from the past year. Highlighted cells lead each row. Open a model for the full picture.
Frequently asked questions
Is Claude Opus 5.5 better than DeepSeek V4.1 Flash?
On Epoch AI's Capabilities Index, Claude Opus 5.5 scores higher (167) than DeepSeek V4.1 Flash (156). The right pick depends on your task, so compare their coding, math, and reasoning scores in the table above.
Which is cheaper, Claude Opus 5.5 or DeepSeek V4.1 Flash?
DeepSeek V4.1 Flash is cheaper on input tokens at $0.14 per million, versus $4.00 (representative OpenRouter pricing).
Which has a larger context window, Claude Opus 5.5 or DeepSeek V4.1 Flash?
Neither: both support up to 1M tokens.
Which is better for coding, Claude Opus 5.5 or DeepSeek V4.1 Flash?
Claude Opus 5.5 ranks higher across coding benchmarks like WebDev Arena and SciCode: 100th vs 75th percentile among the models tracked on Model Beat.
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Benchmarks & model data from Epoch AI (CC BY); pricing & specs from OpenRouter. ECI = Epoch Capabilities Index.