Meta: Llama 3.1 405B (base)
Analysis Summary
Meta's Llama 3.1 405B base is the untuned foundation model from the Llama 3.1 family. With an intelligence index of 17.4 and MMLU-Pro of 0.732, it shows reasonable general knowledge, but as a base model it lacks instruction tuning, making it unsuitable for direct deployment in business workflows without further fine-tuning. It also has no tool use or function calling support, and the 32K context window is a constraint for long-document tasks.
For businesses, this model is primarily relevant as a fine-tuning base for teams with the infrastructure and expertise to adapt it for specific use cases. It is not a drop-in solution for content generation, coding assistance, or agentic workflows in its current form.
At $4.00 per million tokens in and out, it is expensive for a base model, especially given the additional investment required to make it production-ready. Only teams with clear fine-tuning roadmaps and the capacity to run large models should consider it.
Assessed June 6, 2026
Editorial notes
Llama 3.1 405B base from Meta is a large open-weight model with reasonable reasoning benchmarks, but its base (non-instruct) nature, small 32K context, and high pricing limit its practical business utility.
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Performance Profile
How Meta: Llama 3.1 405B (base) compares
Meta: Llama 3.1 405B (base) ranks #199 of 377 AI models we track for overall intelligence, #187 of 314 for coding, #237 of 289 for agentic tasks. Its 33K-token context window is larger than 32% of the models we list. At $4.00 per million input tokens it is cheaper than 7% of comparable models.
About Meta: Llama 3.1 405B (base)
Meta's latest class of model (Llama 3.1) launched with a variety of sizes & flavors. This is the base 405B pre-trained version. It has demonstrated strong performance compared to leading closed-source models in human evaluations. Usage of this model is subject to Meta's Acceptable Use Policy.
Architecture Detail
| Instruct Type | none |
Performance Indices
Source: Artificial Analysis
Benchmark Scores
Intelligence
Technical
Content
Benchmark data from Artificial Analysis and Hugging Face
How does Meta: Llama 3.1 405B (base) stack up?
Compare side-by-side with other professional models.
Model Information
| OpenRouter ID |
meta-llama/llama-3.1-405b
|
| Provider | meta-llama |
| Model Family | Llama 3 |
| Release Date | August 2, 2024 |
| Context Length | 32,768 tokens |
| Max Completion | 32,768 tokens |
| Status | Active |
Pricing
| Token Type | Cost per 1M tokens | Cost per 1K tokens |
|---|---|---|
| Input | $4.00 | $0.004000 |
| Output | $4.00 | $0.004000 |
Leaderboard Categories
External Resources
Frequently asked questions about Meta: Llama 3.1 405B (base)
How much does Meta: Llama 3.1 405B (base) cost?
Meta: Llama 3.1 405B (base) costs $4.00 per million input tokens and $4.00 per million output tokens.
What is the context window of Meta: Llama 3.1 405B (base)?
Meta: Llama 3.1 405B (base) has a context window of 32,768 tokens (33K).
Is Meta: Llama 3.1 405B (base) good for coding?
On our coding benchmark index, Meta: Llama 3.1 405B (base) ranks #187 of 314 models, placing it in the broader range of the field for code generation and debugging.
Who created Meta: Llama 3.1 405B (base)?
Meta: Llama 3.1 405B (base) is developed by Meta and was released on August 2, 2024.
