Model Comparison
DeepSeek-V3 vs Grok-4.1 Fast ReasoningWhich is better in 2026?
Comparing DeepSeek-V3 and Grok-4.1 Fast Reasoning across benchmarks, pricing, and capabilities.
Verdict: DeepSeek-V3 vs Grok-4.1 Fast Reasoning — which is better?
DeepSeek-V3 (by DeepSeek) and Grok-4.1 Fast Reasoning (by xAI) are two of the AI models people compare most. Here is how they stack up on benchmarks, price and capabilities, and which one to pick in 2026.
On price, Grok-4.1 Fast Reasoning is roughly 1.7x cheaper per token on a blended 3:1 input/output basis, which adds up quickly at production volume.
Grok-4.1 Fast Reasoning also accepts a larger context window (2,000,000 input tokens), making it the stronger choice for long documents and large codebases.
Choose DeepSeek-V3 if…
- you need open weights you can self-host or fine-tune
Choose Grok-4.1 Fast Reasoning if…
- cost matters — it's about 1.7x cheaper per token
- you process long inputs — it offers a 2,000,000 token context window
- you want the most recent training data — it shipped Nov 2025
Performance Benchmarks
Comparative analysis across standard metrics
DeepSeek-V3 and Grok-4.1 Fast Reasoningdon't have any common benchmark datasets to compare. They may have been evaluated on different testing suites.
Arena Performance
Human preference votes
Pricing Analysis
Price comparison per million tokens
For input processing, DeepSeek-V3 ($0.27/1M tokens) is 1.4x more expensive than Grok-4.1 Fast Reasoning ($0.20/1M tokens).
For output processing, DeepSeek-V3 ($1.10/1M tokens) is 2.2x more expensive than Grok-4.1 Fast Reasoning ($0.50/1M tokens).
In conclusion, DeepSeek-V3 is more expensive than Grok-4.1 Fast Reasoning.*
* Using a 3:1 ratio of input to output tokens
Context Window
Maximum input and output token capacity
Grok-4.1 Fast Reasoning accepts 2,000,000 input tokens compared to DeepSeek-V3's 131,072 tokens. DeepSeek-V3 can generate longer responses up to 131,072 tokens, while Grok-4.1 Fast Reasoning is limited to 30,000 tokens.
Input Capabilities
Supported data types and modalities
Grok-4.1 Fast Reasoning supports multimodal inputs, whereas DeepSeek-V3 does not.
Grok-4.1 Fast Reasoning can handle both text and other forms of data like images, making it suitable for multimodal applications.
DeepSeek-V3
Grok-4.1 Fast Reasoning
License
Usage and distribution terms
DeepSeek-V3 is licensed under MIT + Model License (Commercial use allowed), while Grok-4.1 Fast Reasoning uses a proprietary license.
License differences may affect how you can use these models in commercial or open-source projects.
MIT + Model License (Commercial use allowed)
Open weights
Proprietary
Closed source
Release Timeline
When each model was launched
DeepSeek-V3 was released on 2024-12-25, while Grok-4.1 Fast Reasoning was released on 2025-11-17.
Grok-4.1 Fast Reasoning is 11 months newer than DeepSeek-V3.
Dec 25, 2024
1.5 years ago
Nov 17, 2025
7 months ago
10mo newerKnowledge Cutoff
When training data ends
Neither model specifies a knowledge cutoff date.
Unable to compare the recency of their training data.
Provider Availability
DeepSeek-V3 is available from DeepSeek. Grok-4.1 Fast Reasoning is available from xAI.
DeepSeek-V3
Grok-4.1 Fast Reasoning
Outputs Comparison
Key Takeaways
DeepSeek-V3
View detailsDeepSeek
Detailed Comparison
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FAQ
Common questions about DeepSeek-V3 vs Grok-4.1 Fast Reasoning.