1M context is now generally available for Opus 4.6 and Sonnet 4.6

2026-03-13 · Source: Claude Blog · Field: Technology & Digital — Artificial Intelligence & Machine Learning, Software Development & Engineering, Cloud Computing & IT Infrastructure · Depth: Intermediate, short

Summary

Claude Opus 4.6 and Sonnet 4.6 models now offer a 1M token context window as generally available, effective March 13, 2026. This expanded context is provided at standard pricing, eliminating previous long-context premiums, with Opus 4.6 priced at $5/$25 per million tokens and Sonnet 4.6 at $3/$15. The update also increases media limits to 600 images or PDF pages per request, a six-fold increase from 100. These models maintain high recall accuracy across the full 1M window, with Opus 4.6 scoring 78.3% on MRCR v2 and Sonnet 4.6 scoring 68.4% on GraphWalks BFS. The 1M context is automatically included for Claude Code Max, Team, and Enterprise users with Opus 4.6, and is available on Claude Platform, Amazon Bedrock, Google Cloud's Vertex AI, and Microsoft Azure Foundry.

Key takeaway

For CTOs and VP of Engineering evaluating large language models for complex tasks, the general availability of 1M context in Claude Opus 4.6 and Sonnet 4.6 at standard pricing significantly reduces the need for context compaction and summarization. You can now process extensive documents, codebases, or conversation histories in a single pass, potentially simplifying agentic system design and improving overall efficiency without incurring premium costs.

Key insights

Claude Opus 4.6 and Sonnet 4.6 now offer 1M token context at standard pricing with enhanced media support.

Principles

• Long context windows improve reasoning.
• Consistent pricing encourages full context utilization.

Method

The models maintain recall accuracy by scoring 78.3% on MRCR v2 (Opus 4.6) and 68.4% on GraphWalks BFS (Sonnet 4.6) at 1M tokens.

In practice

• Load entire codebases or legal contracts.
• Synthesize hundreds of papers for research.
• Debug complex production incidents.

Topics

• Large Language Models
• Context Window
• Claude Opus 4.6
• Claude Sonnet 4.6
• Multimodal AI

Best for: CTO, VP of Engineering/Data, Director of AI/ML, AI Engineer, Machine Learning Engineer, AI Product Manager

Related on AIssential

• Claude Sonnet 4.6: clean upgrade of 4.5, mostly better with some caveats — Sonnet 4.6 offers Opus-level capabilities at Sonnet pricing, but with higher token usage for complex tasks.
• Claude Opus 4.6 in 8 mins! — Opus 4.6 offers a 1M context window and advanced agentic capabilities, but at a premium cost.
• Claude Sonnet 4.6: The Best AI Coding Model Ever! 1M Context, Cheap, & More! (Fully Tested) — Claude Sonnet 4.6 offers Opus-level AI capabilities at half the cost and twice the speed, with a 1M token context.
• Opus 4.6 is here — Claude Opus 4.6 offers enhanced planning, sustained task execution, and superior code debugging with a 1M token context.
• Claude Sonnet 4.6 is now available in Windsurf — Claude Sonnet 4.6 offers frontier-level reasoning at a lower cost, closing the performance gap with Opus.
• Claude Opus 4.6 brings one million token context window to Anthropic's flagship model — Claude Opus 4.6 offers a one-million-token context window with enhanced retrieval and knowledge work performance.

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Editorial summary, takeaway, and curation by AIssential. Original article published by Claude Blog.