Model Comparison
Llama 3.1 405B Instruct vs o3-miniWhich is better in 2026?
o3-mini shows notably better performance in the majority of benchmarks. Llama 3.1 405B Instruct is 2.2x cheaper per token.
Verdict: Llama 3.1 405B Instruct vs o3-mini — which is better?
Llama 3.1 405B Instruct (by Meta) and o3-mini (by OpenAI) 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.
Llama 3.1 405B Instruct outperforms in 1 benchmarks (MMLU), while o3-mini is better at 3 benchmarks (GPQA, IFEval, MATH). o3-mini shows notably better performance in the majority of benchmarks.
On price, Llama 3.1 405B Instruct is roughly 2.2x cheaper per token on a blended 3:1 input/output basis, which adds up quickly at production volume.
o3-mini also accepts a larger context window (200,000 input tokens), making it the stronger choice for long documents and large codebases.
Choose Llama 3.1 405B Instruct if…
- cost matters — it's about 2.2x cheaper per token
- you need open weights you can self-host or fine-tune
Choose o3-mini if…
- you want the strongest raw capability — it leads on 3 of 4 shared benchmarks
- you process long inputs — it offers a 200,000 token context window
- you want the most recent training data — it shipped Jan 2025
Performance Benchmarks
Comparative analysis across standard metrics
Llama 3.1 405B Instruct outperforms in 1 benchmarks (MMLU), while o3-mini is better at 3 benchmarks (GPQA, IFEval, MATH).
o3-mini shows notably better performance in the majority of benchmarks.
Arena Performance
Human preference votes
Pricing Analysis
Price comparison per million tokens
For input processing, Llama 3.1 405B Instruct ($0.89/1M tokens) is 1.2x cheaper than o3-mini ($1.10/1M tokens).
For output processing, Llama 3.1 405B Instruct ($0.89/1M tokens) is 4.9x cheaper than o3-mini ($4.40/1M tokens).
In conclusion, o3-mini is more expensive than Llama 3.1 405B Instruct.*
* Using a 3:1 ratio of input to output tokens
Context Window
Maximum input and output token capacity
o3-mini accepts 200,000 input tokens compared to Llama 3.1 405B Instruct's 128,000 tokens. Llama 3.1 405B Instruct can generate longer responses up to 128,000 tokens, while o3-mini is limited to 100,000 tokens.
License
Usage and distribution terms
Llama 3.1 405B Instruct is licensed under Llama 3.1 Community License, while o3-mini uses a proprietary license.
License differences may affect how you can use these models in commercial or open-source projects.
Llama 3.1 Community License
Open weights
Proprietary
Closed source
Release Timeline
When each model was launched
Llama 3.1 405B Instruct was released on 2024-07-23, while o3-mini was released on 2025-01-30.
o3-mini is 6 months newer than Llama 3.1 405B Instruct.
Jul 23, 2024
2.0 years ago
Jan 30, 2025
1.5 years ago
6mo newerKnowledge Cutoff
When training data ends
o3-mini has a documented knowledge cutoff of 2023-09-30, while Llama 3.1 405B Instruct's cutoff date is not specified.
We can confirm o3-mini's training data extends to 2023-09-30, but cannot make a direct comparison without Llama 3.1 405B Instruct's cutoff date.
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Sep 2023
Provider Availability
Llama 3.1 405B Instruct is available from Lambda, DeepInfra, Fireworks, Bedrock, Together, Hyperbolic, Google, Replicate. o3-mini is available from Azure, OpenAI.
Llama 3.1 405B Instruct
o3-mini
Outputs Comparison
Key Takeaways
o3-mini
View detailsOpenAI
Detailed Comparison
Interactive Arena
Judge for yourself.
Run your own prompts against Llama 3.1 405B Instruct and o3-mini side-by-side, then vote on the output you prefer.
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FAQ
Common questions about Llama 3.1 405B Instruct vs o3-mini.