Mistral Medium 3.5 vs o3
Mistral Medium 3.5 and o3 are closely matched at 26.6 and 30.8 on the LLM Stats Score. Mistral Medium 3.5 is 1.2x cheaper per token.
Mistral AI · OpenAI · Updated for 2026
Which is better?
Mistral Medium 3.5 and o3 are closely matched on the overall LLM Stats Score at 26.6 and 30.8.
In the 4 individual benchmarks reported for both models, o3 wins 3; this is a narrower head-to-head signal than the composite indexes.
On price, Mistral Medium 3.5 is roughly 1.2x cheaper per token on a blended 3:1 input/output basis, which adds up quickly at production volume.
Mistral Medium 3.5 also accepts a larger context window (256,000 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 Mistral Medium 3.5
- cost matters — it's about 1.2x cheaper per token
- you process long inputs — it offers a 256,000 token context window
- you want the most recent training data — it shipped Apr 2026
- you need open weights you can self-host or fine-tune
Choose o3
- you value its reported benchmark strengths — it wins 3 of 4 exact shared results
At a glance
The differences that matter most.
Capability indexes
Additional strengths measured across groups of related public benchmarks
Individual benchmarks
11 reported for Mistral Medium 3.5 · 22 for o3
Mistral Medium 3.5 outperforms in 1 benchmarks (SWE-Bench Verified), while o3 is better at 3 benchmarks (AIME 2025, BrowseComp, COLLIE).
o3 shows notably better performance in the majority of benchmarks.
Human preference
Blind head-to-head votes and playground preference scores
Pricing Analysis
Price comparison per million tokens
For input processing, Mistral Medium 3.5 ($1.50/1M tokens) is 1.3x cheaper than o3 ($2.00/1M tokens).
For output processing, Mistral Medium 3.5 ($7.50/1M tokens) is 1.1x cheaper than o3 ($8.00/1M tokens).
In conclusion, o3 is more expensive than Mistral Medium 3.5.*
* Using a 3:1 ratio of input to output tokens
Context Window
Maximum input and output token capacity
Mistral Medium 3.5 accepts 256,000 input tokens compared to o3's 200,000 tokens. Mistral Medium 3.5 can generate longer responses up to 256,000 tokens, while o3 is limited to 100,000 tokens.
Input capabilities
Documented input modalities across available providers
Both Mistral Medium 3.5 and o3 support multimodal inputs.
They are both capable of processing various types of data, offering versatility in application.
Mistral Medium 3.5
o3
License
Usage and distribution terms
Mistral Medium 3.5 is licensed under Modified MIT License, while o3 uses a proprietary license.
License differences may affect how you can use these models in commercial or open-source projects.
Modified MIT License
Open weights
Proprietary
Closed source
Release Timeline
When each model was launched
Mistral Medium 3.5 was released on 2026-04-29, while o3 was released on 2025-04-16.
Mistral Medium 3.5 is 13 months newer than o3.
Apr 29, 2026
5 months ago
1.0yr newerApr 16, 2025
1.5 years ago
Knowledge Cutoff
When training data ends
o3 has a documented knowledge cutoff of 2024-05-31, while Mistral Medium 3.5's cutoff date is not specified.
We can confirm o3's training data extends to 2024-05-31, but cannot make a direct comparison without Mistral Medium 3.5's cutoff date.
—
May 2024
Provider Availability
Mistral Medium 3.5 is available from Mistral AI. o3 is available from OpenAI.
Mistral Medium 3.5
o3
Outputs Comparison
Judge for yourself.
Run your own prompts against Mistral Medium 3.5 and o3 side-by-side, then vote on the output you prefer.
FAQ
Common questions about Mistral Medium 3.5 vs o3.