Claude Opus 5.5 vs DeepSeek-R1
Comparing Claude Opus 5.5 and DeepSeek-R1 across benchmarks, pricing, and capabilities.
Anthropic · DeepSeek · Updated for 2026
Which is better?
Claude Opus 5.5 and DeepSeek-R1 trade strengths across price, capabilities, and technical limits. The better choice depends on the workload.
On price, DeepSeek-R1 is roughly 8.3x cheaper per token on a blended 3:1 input/output basis, which adds up quickly at production volume.
Claude Opus 5.5 also accepts a larger context window (1,000,000 input tokens), making it the stronger choice for long documents and large codebases.
Based on current LLM Stats indexes, shared benchmarks, pricing, and model metadata for 2026.
Choose Claude Opus 5.5
- you process long inputs — it offers a 1,000,000 token context window
- you want the most recent training data — it shipped Sep 2026
Choose DeepSeek-R1
- cost matters — it's about 8.3x cheaper per token
- you need open weights you can self-host or fine-tune
At a glance
The differences that matter most.
Individual benchmarks
31 reported for Claude Opus 5.5 · 0 for DeepSeek-R1
Claude Opus 5.5 and DeepSeek-R1don't have any common benchmark datasets to compare. They may have been evaluated on different testing suites.
Human preference
Blind head-to-head votes and playground preference scores
Pricing Analysis
Price comparison per million tokens
For input processing, Claude Opus 5.5 ($4.00/1M tokens) is 7.3x more expensive than DeepSeek-R1 ($0.55/1M tokens).
For output processing, Claude Opus 5.5 ($20.00/1M tokens) is 9.1x more expensive than DeepSeek-R1 ($2.19/1M tokens).
In conclusion, Claude Opus 5.5 is more expensive than DeepSeek-R1.*
* Using a 3:1 ratio of input to output tokens
Context Window
Maximum input and output token capacity
Claude Opus 5.5 accepts 1,000,000 input tokens compared to DeepSeek-R1's 131,072 tokens. DeepSeek-R1 can generate longer responses up to 131,072 tokens, while Claude Opus 5.5 is limited to 128,000 tokens.
Input capabilities
Documented input modalities across available providers
Claude Opus 5.5 supports multimodal inputs, whereas DeepSeek-R1 does not.
Claude Opus 5.5 can handle both text and other forms of data like images, making it suitable for multimodal applications.
Claude Opus 5.5
DeepSeek-R1
License
Usage and distribution terms
Claude Opus 5.5 is licensed under a proprietary license, while DeepSeek-R1 uses MIT.
License differences may affect how you can use these models in commercial or open-source projects.
Proprietary
Closed source
MIT
Open weights
Release Timeline
When each model was launched
Claude Opus 5.5 was released on 2026-09-22, while DeepSeek-R1 was released on 2025-01-20.
Claude Opus 5.5 is 20 months newer than DeepSeek-R1.
Sep 22, 2026
0 days ago
1.7yr newerJan 20, 2025
1.7 years ago
Knowledge Cutoff
When training data ends
Claude Opus 5.5 has a documented knowledge cutoff of 2026-06-01, while DeepSeek-R1's cutoff date is not specified.
We can confirm Claude Opus 5.5's training data extends to 2026-06-01, but cannot make a direct comparison without DeepSeek-R1's cutoff date.
Jun 2026
—
Provider Availability
Claude Opus 5.5 is available from Anthropic. DeepSeek-R1 is available from DeepSeek, DeepInfra, Together, Fireworks.
Claude Opus 5.5
DeepSeek-R1
Outputs Comparison
Judge for yourself.
Run your own prompts against Claude Opus 5.5 and DeepSeek-R1 side-by-side, then vote on the output you prefer.
FAQ
Common questions about Claude Opus 5.5 vs DeepSeek-R1.