Skip to main content
idapt
HomeAI ModelsExploreResourcesPricing
Sign inUse for Free
  • Home
  • Pricing
  • AI Models
  • Skills
  • Image models
  • Voice models
  • Video models
  • Rankings
  • Multi-Model Chat
  • Agents
  • Computers
  • Drive
  • Actions
  • AI Gateway
  • All features →
  • Blog
  • About
  • Comparisons
  • Benchmarks
  • Model Match
  • Demos
  • Help center
  • FAQ
  • Privacy
  • Support
  • Developers
  • Quickstarts
  • API reference
  • API pricing
  • CLI
  • MCP
  • Migrate
  • Downloads
  • Desktop
© idapt[email protected]TermsPrivacy PolicyLegal noticeReport content
X (Twitter)Discord

Llama 3.1 405B vs Claude Opus 5.5

At a glance

Meta's largest open-weight model at 405B parameters.

63131K ctx#66/92

Anthropic's new flagship for demanding reasoning, coding, and long-horizon agentic work, succeeding Claude Opus 5.

1M ctx$4.00/$20.00 per M
Demos
All demos

No shared demos for these models yet.

AI Output
All AI outputs

No captured outputs for these models yet.

Benchmarks
See rankings
CodingInsufficient data
AgenticInsufficient data
Sources:Epoch ECI·Epoch AI· as of 2026-10-02
Capability
CapabilityECI62.7
Reasoning & Knowledge
Graduate Science50.9%Factual Recall—
Math
Math Problems49.8%Competition Math9.7%
Agentic
Novel Reasoning—
Reasoning
CodingInsufficient data
AgenticInsufficient data
Sources:Epoch AI·OpenRouter· as of 2026-10-02
Capability
Capability—
Reasoning & Knowledge
Graduate Science78%90.6%Factual Recall72.2%
Math
Math Problems—Competition Math929%100.0%
Agentic
Novel Reasoning92.5%
Specs
131K
Context
16K
Max output
—
Released
1M
Context
128K
Max output
Sep 2026
Released
Capabilities
Vision
Audio
Reasoning
Vision
Audio
Reasoning
Pricing
Pricing not available
Live pricing, shown before you run
Input$4.00/M tokens
Output$20.00/M tokens
Cache read$0.20/M tokens
Cache write$5.00/M tokens
Web search$0.01/search
Chat with Llama 3.1 405BGo to model
Chat with Claude Opus 5.5Go to model
Frequently Asked Questions: Llama 3.1 405B vs Claude Opus 5.5▼

Which is better, Llama 3.1 405B or Claude Opus 5.5?

▼

Both Llama 3.1 405B and Claude Opus 5.5 are capable AI models. The best choice depends on your specific use case: consider pricing, context window, speed, and which capabilities (vision, reasoning, audio) you need.

Which has a larger context window, Llama 3.1 405B or Claude Opus 5.5?

▼

Claude Opus 5.5 has a larger context window: Llama 3.1 405B supports 131K tokens vs Claude Opus 5.5 at 1M tokens.

Do both Llama 3.1 405B and Claude Opus 5.5 support vision?

▼

Claude Opus 5.5 supports vision/image input, but Llama 3.1 405B does not.

What are the key differences between Llama 3.1 405B and Claude Opus 5.5?

▼

Key differences: only Claude Opus 5.5 supports vision input; only Claude Opus 5.5 offers extended reasoning mode. Compare full specs on this page.

Which model should I choose for my use case?

▼

If cost is your priority, choose the cheaper option. If you need the highest intelligence for complex tasks, pick the higher-scoring model. For long documents or codebases, choose the larger context window. You can try both Llama 3.1 405B and Claude Opus 5.5 for free on idapt.app to see which performs better for your specific needs.

Open in App