GPT-4 Turbo vs Grok-4.1 Fast Reasoning
Comparing GPT-4 Turbo and Grok-4.1 Fast Reasoning across benchmarks, pricing, and capabilities.
OpenAI · xAI · Updated for 2026
Which is better?
GPT-4 Turbo and Grok-4.1 Fast Reasoning trade strengths across price, capabilities, and technical limits. The better choice depends on the workload.
On price, Grok-4.1 Fast Reasoning is roughly 54.5x 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.
Based on current benchmark, pricing, and model metadata for 2026.
Choose GPT-4 Turbo
- you want predictable pricing at $10.00/M input and $30.00/M output
Choose Grok-4.1 Fast Reasoning
- cost matters — it's about 54.5x 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
At a glance
The differences that matter most.
Performance Benchmarks
Comparative analysis across standard metrics
GPT-4 Turbo 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
Playground indexes and blind preference scores
Pricing Analysis
Price comparison per million tokens
For input processing, GPT-4 Turbo ($10.00/1M tokens) is 50.0x more expensive than Grok-4.1 Fast Reasoning ($0.20/1M tokens).
For output processing, GPT-4 Turbo ($30.00/1M tokens) is 60.0x more expensive than Grok-4.1 Fast Reasoning ($0.50/1M tokens).
In conclusion, GPT-4 Turbo 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 GPT-4 Turbo's 128,000 tokens. Grok-4.1 Fast Reasoning can generate longer responses up to 30,000 tokens, while GPT-4 Turbo is limited to 4,096 tokens.
Input Capabilities
Supported data types and modalities
Grok-4.1 Fast Reasoning supports multimodal inputs, whereas GPT-4 Turbo does not.
Grok-4.1 Fast Reasoning can handle both text and other forms of data like images, making it suitable for multimodal applications.
GPT-4 Turbo
Grok-4.1 Fast Reasoning
License
Usage and distribution terms
Both models are licensed under proprietary licenses.
Both models have usage restrictions defined by their respective organizations.
Proprietary
Closed source
Proprietary
Closed source
Release Timeline
When each model was launched
GPT-4 Turbo was released on 2024-04-09, while Grok-4.1 Fast Reasoning was released on 2025-11-17.
Grok-4.1 Fast Reasoning is 20 months newer than GPT-4 Turbo.
Apr 9, 2024
2.4 years ago
Nov 17, 2025
9 months ago
1.6yr newerKnowledge Cutoff
When training data ends
GPT-4 Turbo has a documented knowledge cutoff of 2023-12-31, while Grok-4.1 Fast Reasoning's cutoff date is not specified.
We can confirm GPT-4 Turbo's training data extends to 2023-12-31, but cannot make a direct comparison without Grok-4.1 Fast Reasoning's cutoff date.
Dec 2023
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Provider Availability
GPT-4 Turbo is available from Azure, OpenAI. Grok-4.1 Fast Reasoning is available from xAI.
GPT-4 Turbo
Grok-4.1 Fast Reasoning
Outputs Comparison
Judge for yourself.
Run your own prompts against GPT-4 Turbo and Grok-4.1 Fast Reasoning side-by-side, then vote on the output you prefer.
FAQ
Common questions about GPT-4 Turbo vs Grok-4.1 Fast Reasoning.