Grok 4 Fast vs Mistral Medium 3.5
Grok 4 Fast and Mistral Medium 3.5 are closely matched at 31.7 and 26.9 on the LLM Stats Score. Grok 4 Fast is 10.9x cheaper per token.
xAI · Mistral AI · Updated for 2026
Which is better?
Grok 4 Fast and Mistral Medium 3.5 are closely matched on the overall LLM Stats Score at 31.7 and 26.9.
The models split the 2 individual benchmarks reported for both models evenly.
On price, Grok 4 Fast is roughly 10.9x cheaper per token on a blended 3:1 input/output basis, which adds up quickly at production volume.
Grok 4 Fast 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 LLM Stats indexes, shared benchmarks, pricing, and model metadata for 2026.
Choose Grok 4 Fast
- cost matters — it's about 10.9x cheaper per token
- you process long inputs — it offers a 2,000,000 token context window
Choose Mistral Medium 3.5
- you want the most recent training data — it shipped Apr 2026
- you need open weights you can self-host or fine-tune
At a glance
The differences that matter most.
Capability indexes
Additional strengths measured across groups of related public benchmarks
Individual benchmarks
7 reported for Grok 4 Fast · 11 for Mistral Medium 3.5
Grok 4 Fast outperforms in 1 benchmarks (AIME 2025), while Mistral Medium 3.5 is better at 1 benchmark (BrowseComp).
Both models are evenly matched across the benchmarks.
Human preference
Blind head-to-head votes and playground preference scores
Pricing Analysis
Price comparison per million tokens
For input processing, Grok 4 Fast ($0.20/1M tokens) is 7.5x cheaper than Mistral Medium 3.5 ($1.50/1M tokens).
For output processing, Grok 4 Fast ($0.50/1M tokens) is 15.0x cheaper than Mistral Medium 3.5 ($7.50/1M tokens).
In conclusion, Mistral Medium 3.5 is more expensive than Grok 4 Fast.*
* Using a 3:1 ratio of input to output tokens
Context Window
Maximum input and output token capacity
Grok 4 Fast accepts 2,000,000 input tokens compared to Mistral Medium 3.5's 256,000 tokens. Mistral Medium 3.5 can generate longer responses up to 256,000 tokens, while Grok 4 Fast is limited to 30,000 tokens.
Input capabilities
Documented input modalities across available providers
Both Grok 4 Fast and Mistral Medium 3.5 support multimodal inputs.
They are both capable of processing various types of data, offering versatility in application.
Grok 4 Fast
Mistral Medium 3.5
License
Usage and distribution terms
Grok 4 Fast is licensed under a proprietary license, while Mistral Medium 3.5 uses Modified MIT License.
License differences may affect how you can use these models in commercial or open-source projects.
Proprietary
Closed source
Modified MIT License
Open weights
Release Timeline
When each model was launched
Grok 4 Fast was released on 2025-08-28, while Mistral Medium 3.5 was released on 2026-04-29.
Mistral Medium 3.5 is 8 months newer than Grok 4 Fast.
Aug 28, 2025
1.1 years ago
Apr 29, 2026
5 months ago
8mo newerKnowledge Cutoff
When training data ends
Neither model specifies a knowledge cutoff date.
Unable to compare the recency of their training data.
Provider Availability
Grok 4 Fast is available from xAI. Mistral Medium 3.5 is available from Mistral AI.
Grok 4 Fast
Mistral Medium 3.5
Outputs Comparison
Judge for yourself.
Run your own prompts against Grok 4 Fast and Mistral Medium 3.5 side-by-side, then vote on the output you prefer.
FAQ
Common questions about Grok 4 Fast vs Mistral Medium 3.5.