LLM Reference

Claude Opus 4.5 vs Llama 3.1 405B Instruct

Claude Opus 4.5 (2025) and Llama 3.1 405B Instruct (2024) are frontier reasoning models from Anthropic and AI at Meta. Claude Opus 4.5 ships a 200k-token context window, while Llama 3.1 405B Instruct ships a 128k-token context window. On pricing, Llama 3.1 405B Instruct costs $2.40/1M input tokens versus $5/1M for the alternative. 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 4.5 only for coding workflow support.

Decision scorecard

Local evidence first
SignalClaude Opus 4.5Llama 3.1 405B Instruct
Best forreasoning-heavy apps, multimodal apps, and tool-calling agentsprovider-routed production
Decision fitCoding, RAG, and AgentsRAG, Long context, and Classification
Context window200k128k
Cheapest output$25/1M tokens$2.40/1M tokens
Provider routes6 tracked11 tracked
Shared benchmarks0 shared0 shared

Decision tradeoffs

Choose Claude Opus 4.5 when...
  • Claude Opus 4.5 has the larger context window for long prompts, retrieval packs, or transcript analysis.
  • Claude Opus 4.5 uniquely exposes Vision, Multimodal, and Reasoning in local model data.
  • Local decision data tags Claude Opus 4.5 for Coding, RAG, and Agents.
Choose Llama 3.1 405B Instruct when...
  • 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 route 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.

Lower estimate Llama 3.1 405B Instruct

Claude Opus 4.5

$10,250

Cheapest tracked route/tier: Microsoft Foundry

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

Claude Opus 4.5 -> Llama 3.1 405B Instruct
  • 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.
Llama 3.1 405B Instruct -> Claude Opus 4.5
  • Provider overlap exists on Microsoft Foundry, GCP Vertex AI, and AWS Bedrock; start route-level A/B tests there.
  • Claude Opus 4.5 is $22.60/1M tokens higher on cheapest tracked output pricing, so quality gains need to justify the spend.
  • Claude Opus 4.5 adds Vision, Multimodal, and Reasoning in local capability data.

Specs

Specification
Released2025-11-012024-07-23
Context window200k128k
Parameters405B
ArchitectureDecoder OnlyDecoder Only
LicenseProprietaryLlama 3 Community
OpennessProprietaryOpen weights
WeightsNot releasedAvailable
CodeUnknownUnknown
Commercial useCommercial use: conditionalCommercial use: conditional
Knowledge cutoff2025-122023-12

Pricing and availability

Pricing attributeClaude Opus 4.5Llama 3.1 405B Instruct
Input price$5/1M tokens$2.40/1M tokens
Output price$25/1M tokens$2.40/1M tokens
Providers

Capabilities

CapabilityClaude Opus 4.5Llama 3.1 405B Instruct
VisionYesNo
MultimodalYesNo
ReasoningYesNo
JSON / Tool useYesNo
Structured outputsYesYes
Code executionYesNo
IDE integrationNoNo
Computer useNoNo
Parallel agentsNoNo

Benchmarks

No shared benchmark scores are currently available for this pair.

Continue comparing

Last reviewed: 2026-07-26. Data sourced from public model cards and provider documentation.