Claude's 1M Context Window at Standard Pricing: The Real Cost Math
March 16, 2026 · 10 min read · Cost Analysis, Claude Code, Guide
On March 13, 2026, Anthropic made the 1M token context window generally available for Claude Opus 4.6 and Sonnet 4.6 at standard pricing — no long-context surcharge. A 900K-token request costs the same per-token rate as a 9K one. Opus 4.6: $5/$25 per MTok. Sonnet 4.6: $3/$15 per MTok.
What Changed
No beta header required for 200K+ requests, full rate limits at every context length, and 6x media capacity (600 images/PDFs, up from 100). 1M context is available in Claude Code for Max ($100+/mo), Team, and Enterprise users — Pro plan stays at 200K.
The Real Cost
A full 1M-token input + 100K output on Opus 4.6 costs $7.50 per API call. Sonnet 4.6: $4.50. Agentic workflows making 5-10 calls per task can run $20-50. Prompt caching cuts input costs 90% ($0.50/MTok cached vs $5.00 uncached on Opus).
Benchmark Performance
Opus 4.6 scores 78.3% on MRCR v2 at 1M tokens — 2x GPT-5.4 (36%) and 3x Gemini 3.1 Pro (26.3%). At 256K, Opus hits 92-93% vs GPT-5.2's 63.9%. Claude Code remains the only tool with native 1M context; Cursor (~200K), Copilot (~128K), and Windsurf (~128K) lag behind.
Optimization Tips
Use scoped prompts (80% token reduction). Enable prompt caching ($45 savings per 10-call agentic task). Batch related work into single sessions (40% lower costs). Use Sonnet for exploration, Opus for execution. Track costs with BurnRate: brew install burnrate-dev/tap/burnrate
Sources: Claude Blog (1M Context GA), Anthropic API Pricing, InfoQ (Opus 4.6 Context Compaction), Hacker News discussion, Cursor Forum.