Claude Opus 4.6 vs Llama 3.1 405B Instruct
Claude Opus 4.6 (2026) and Llama 3.1 405B Instruct (2024) are frontier reasoning models from Anthropic and AI at Meta. Claude Opus 4.6 ships a 1m-token context window, while Llama 3.1 405B Instruct ships a 128k-token context window. On Massive Multitask Language Understanding, Claude Opus 4.6 leads by 2.5 pts. This comparison covers specs, pricing, API access, capabilities, benchmarks, input and output token costs, and production fit for coding and agent workloads.
Llama 3.1 405B Instruct is ~108% cheaper at $2.40/1M; pay for Claude Opus 4.6 only for coding workflow support.
Decision scorecard
Local evidence first| Signal | Claude Opus 4.6 | Llama 3.1 405B Instruct |
|---|---|---|
| Best for | reasoning-heavy apps, multimodal apps, and tool-calling agents | provider-routed production |
| Decision fit | Coding, RAG, and Agents | RAG, Long context, and Classification |
| Context window | 1m | 128k |
| Cheapest output | $25/1M tokens | $2.40/1M tokens |
| Provider routes | 6 tracked | 11 tracked |
| Shared benchmarks | Massive Multitask Language Understanding leader | 1 rows |
Decision tradeoffs
- Claude Opus 4.6 holds a shared-benchmark lead on Massive Multitask Language Understanding, ahead by 2.5 points.
- Claude Opus 4.6 has the larger context window for long prompts, retrieval packs, or transcript analysis.
- Claude Opus 4.6 uniquely exposes Vision, Multimodal, and Reasoning in local model data.
- Local decision data tags Claude Opus 4.6 for Coding, RAG, and Agents.
- Llama 3.1 405B Instruct has the lower cheapest tracked output price at $2.40/1M tokens.
- Llama 3.1 405B Instruct has broader tracked provider coverage for fallback and procurement flexibility.
- Local decision data tags Llama 3.1 405B Instruct for RAG, Long context, and Classification.
Monthly cost at traffic
Estimate token spend from the cheapest tracked input and output route or tier on this page.
Claude Opus 4.6
$10,250
Cheapest tracked route/tier: Anthropic
Llama 3.1 405B Instruct
$2,520
Cheapest tracked route/tier: AWS Bedrock
Estimated monthly gap: $7,730. Batch, cache, alternate speed tiers, and negotiated pricing are excluded from this local estimate.
Switch friction
- Provider overlap exists on Microsoft Foundry, AWS Bedrock, and GCP Vertex AI; start route-level A/B tests there.
- Llama 3.1 405B Instruct is $22.60/1M tokens lower on cheapest tracked output pricing before cache, batch, or negotiated discounts.
- Check replacement coverage for Vision, Multimodal, and Reasoning before moving production traffic.
- Provider overlap exists on AWS Bedrock, GCP Vertex AI, and Microsoft Foundry; start route-level A/B tests there.
- Claude Opus 4.6 is $22.60/1M tokens higher on cheapest tracked output pricing, so quality gains need to justify the spend.
- Claude Opus 4.6 adds Vision, Multimodal, and Reasoning in local capability data.
Specs
| Specification | ||
|---|---|---|
| Released | 2026-02-05 | 2024-07-23 |
| Context window | 1m | 128k |
| Parameters | — | 405B |
| Architecture | decoder only | decoder only |
| License | Proprietary | Llama 3 Community |
| Openness | Proprietary | Open weights |
| Commercial use | Commercial use with conditions | Commercial use with conditions |
| Knowledge cutoff | 2025-12 | 2023-12 |
Pricing and availability
| Pricing attribute | Claude Opus 4.6 | Llama 3.1 405B Instruct |
|---|---|---|
| Input price | $5/1M tokens | $2.40/1M tokens |
| Output price | $25/1M tokens | $2.40/1M tokens |
| Providers |
Capabilities
| Capability | Claude Opus 4.6 | Llama 3.1 405B Instruct |
|---|---|---|
| Vision | Yes | No |
| Multimodal | Yes | No |
| Reasoning | Yes | No |
| Function calling | Yes | No |
| Tool use | Yes | No |
| Structured outputs | Yes | Yes |
| Code execution | Yes | No |
| IDE integration | No | No |
| Computer use | No | No |
| Parallel agents | No | No |
Benchmarks
| Benchmark | Claude Opus 4.6 | Llama 3.1 405B Instruct |
|---|---|---|
| Massive Multitask Language Understanding | 91.1 | 88.6 |
Deep dive
On shared benchmark coverage, Massive Multitask Language Understanding has Claude Opus 4.6 at 91.1 and Llama 3.1 405B Instruct at 88.6, with Claude Opus 4.6 ahead by 2.5 points. The largest visible gap is 2.5 points on Massive Multitask Language Understanding, which matters most when that benchmark mirrors your workload. Treat isolated benchmark wins as directional, because provider routing, prompt style, and tool access can move real application results.
The capability footprint differs most on vision: Claude Opus 4.6, multimodal input: Claude Opus 4.6, reasoning mode: Claude Opus 4.6, function calling: Claude Opus 4.6, tool use: Claude Opus 4.6, and code execution: Claude Opus 4.6. Both models share structured outputs, so the practical split is not just feature count. Use those differences to decide whether the page is about raw model quality, agentic coding support, multimodal ingestion, or predictable structured API behavior.
For cost, Claude Opus 4.6 lists $5/1M input and $25/1M output tokens on the cheapest tracked provider, while Llama 3.1 405B Instruct lists $2.40/1M input and $2.40/1M output tokens on the cheapest tracked provider. A 70/30 input-output blend puts Llama 3.1 405B Instruct lower by about $8.60 per million blended tokens. Availability is 6 providers versus 11, so concentration risk also matters.
Choose Claude Opus 4.6 when coding workflow support and larger context windows are central to the workload. Choose Llama 3.1 405B Instruct when provider fit, lower input-token cost, and broader provider choice are more important. For production, rerun your own prompts through the exact provider, region, and tool stack you plan to ship.
FAQ
Which has a larger context window, Claude Opus 4.6 or Llama 3.1 405B Instruct?
Claude Opus 4.6 supports 1m tokens, while Llama 3.1 405B Instruct supports 128k tokens. That gap matters most for long documents, large codebases, retrieval-heavy agents, and conversations where earlier context must remain visible.
Which is cheaper, Claude Opus 4.6 or Llama 3.1 405B Instruct?
Llama 3.1 405B Instruct is cheaper on tracked token pricing. Claude Opus 4.6 costs $5/1M input and $25/1M output tokens. Llama 3.1 405B Instruct costs $2.40/1M input and $2.40/1M output tokens. Provider discounts or batch pricing can still change the final bill.
Is Claude Opus 4.6 or Llama 3.1 405B Instruct open source?
Claude Opus 4.6 is listed under Proprietary. Llama 3.1 405B Instruct is listed under Llama 3 Community. License labels affect whether you can self-host, redistribute weights, or rely only on hosted APIs, so confirm the upstream license before deployment.
Which is better for vision, Claude Opus 4.6 or Llama 3.1 405B Instruct?
Claude Opus 4.6 has the clearer documented vision signal in this comparison. If vision is mission-critical, validate it against the provider endpoint because model-level support and API-level exposure can differ.
Which is better for multimodal input, Claude Opus 4.6 or Llama 3.1 405B Instruct?
Claude Opus 4.6 has the clearer documented multimodal input signal in this comparison. If multimodal input is mission-critical, validate it against the provider endpoint because model-level support and API-level exposure can differ.
Where can I run Claude Opus 4.6 and Llama 3.1 405B Instruct?
Claude Opus 4.6 is available on Anthropic, AWS Bedrock, GCP Vertex AI, Microsoft Foundry, and OpenRouter. Llama 3.1 405B Instruct is available on OctoAI API (Deprecated), Together AI, Fireworks AI, IBM watsonx, and Scale AI GenAI Platform. Provider coverage can affect latency, region availability, compliance posture, and fallback options.
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Last reviewed: 2026-05-22. Data sourced from public model cards and provider documentation.