Meta: Llama 3.1 405B (base)
Analysis Summary
Meta's Llama 3.1 405B base is a text model with measured results for reasoning, coding-adjacent tasks, instruction following, and agentic benchmarks. It has a 32K context window and no tool-use or function-calling support listed. The base designation is an important practical distinction: this entry does not establish the instruction-following behavior expected from a ready-to-use assistant model.
Businesses should be cautious about using it directly in client workflows without confirming that its outputs fit their prompting and integration setup. The listed input and output prices are $4 per million tokens, making experimentation costly compared with cheaper options. It may be worth a specialized evaluation where its measured capabilities match a specific need, but it is not a practical default for routine agency work.
Assessed September 23, 2026
Editorial notes
The Llama 3.1 405B base entry has measured reasoning and agentic results, but lacks instruction-tuned labeling and tool-use support in the supplied data. High token prices and a 32K context window limit its workflow appeal.
The DFO score ranks models on the Artificial Analysis Intelligence Index and is refreshed as new models launch. The write-up and verdict are our own. Feedback?
DFO Verdict
The Llama 3.1 405B base entry has measured reasoning and agentic results, but lacks instruction-tuned labeling and tool-use support in the supplied data. High token prices and a 32K context window limit its workflow appeal.
Benchmarks
Artificial Analysis data refreshed Oct 8, 2026. Arena ratings from the Oct 2, 2026 text leaderboard, with style control. Bars: magenta = reasoning, ink = coding and agents, cyan = instructions and long context.
Artificial Analysis no longer lists this model, so its indexes are converted from their older scale to stay comparable.
How Meta: Llama 3.1 405B (base) compares
Meta: Llama 3.1 405B (base) ranks #361 of 435 AI models we track for overall intelligence, #101 of 181 for agentic tasks. Its 33K-token context window is larger than 26% of the models we list. At $4.00 per million input tokens it is cheaper than 6% of comparable models.
Dark bar = input · light bar = output, scaled to the priciest peer.
1M tokens ≈ 8 full-length novels or ~2,500 pages of business documents in a single request.
Pricing
| Token Type | Cost per 1M tokens | Cost per 1K tokens |
|---|---|---|
| Input | $4.00 | $0.004000 |
| Output | $4.00 | $0.004000 |
What would Meta: Llama 3.1 405B (base) cost your business?
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A website chatbot handling around 100 customer conversations a day, a few short messages each.
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Talk to our teamAbout 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.
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).
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.