Claude Sonnet 4.6: Near-Opus Power at One-Fifth the Cost

Claude Sonnet 4.6 delivers near-flagship intelligence at $3/$15 per million tokens — one-fifth the cost of Opus 4.6. Released on February 17th, 2026, it scores 79.6% on SWE-bench Verified and 72.5% on OSWorld, making it the strongest mid-tier AI model available for agentic coding and knowledge work.

For development teams running Claude in production, this changes the cost calculus entirely. We operate 15 automated cron jobs on Claude Opus 4.6 daily. Sonnet 4.6 forces a serious migration question: can you get 95% of the capability at 20% of the price?

What Sonnet 4.6 Actually Delivers

According to Anthropic's official announcement, Sonnet 4.6 is a "full upgrade" across coding, computer use, long-context reasoning, agent planning, knowledge work, and design. Claude Sonnet 4.6 The model features a 1M token context window in beta — matching Opus 4.6's capacity at a fraction of the cost.

The benchmark numbers tell a compelling story:

• SWE-bench Verified: 79.6% — state-of-the-art for agentic coding
• OSWorld: 72.5%, up from 61.4% on Sonnet 4.5 — a massive 18% relative improvement in computer use
• Tool use: 61.3%, up from 43.8% on Sonnet 4.5
• Agentic financial analysis: Beats both GPT-5.2 and Gemini 3 Pro on GDPVal office tasks

Developers with early access preferred Sonnet 4.6 over its predecessor by a wide margin. Many even preferred it over Claude Opus 4.5, Anthropic's flagship model from November 2025, according to Anthropic's internal testing.

The Pricing Equation

The math is straightforward. Claude Sonnet 4.6 Here is what each model costs per million tokens:

Sonnet 4.6 costs exactly one-fifth of Opus 4.6 on both input and output. For a team processing 100M tokens per month, that is the difference between a $9,000 bill and a $1,800 bill. The savings compound quickly at scale.

According to VentureBeat, pricing remains identical to Sonnet 4.5 — Anthropic delivered a major capability upgrade without raising costs.

Agentic Coding: Where Sonnet 4.6 Shines

The 79.6% SWE-bench Verified score is not just a number. Claude Sonnet 4.6 SWE-bench tests a model's ability to resolve real GitHub issues autonomously — reading codebases, understanding bug reports, and generating working patches. This is the benchmark that matters most for teams using AI in development workflows.

According to Anthropic, their engineers using Claude Code have seen a 150% increase in pull requests per engineer. Sonnet 4.6 is positioned as the default engine for Claude Code for most users, bringing this productivity gain to a wider audience at lower cost.

The model also excels at autonomous multi-step tasks. In demonstrations, it built a Minecraft clone, an F1 racing simulation, a macOS-style frontend, and a marble labyrinth game — all without manual intervention. It autonomously set up a complete browser automation project from scratch.

Computer Use: From Experimental to Production-Ready

OSWorld measures a model's ability to operate real desktop software — Chrome, LibreOffice, VS Code — using virtual mouse and keyboard input, with no special APIs. Claude Sonnet 4.6 Sonnet 4.6's 72.5% score represents a step change from earlier models.

According to Anthropic, early users report "near humanlike performance" on tasks like complex spreadsheet manipulation and multi-step web form execution. The model navigates multiple browser tabs, pulls data from disparate sources, and completes workflows that previously required custom integrations.

Anthropic also notes that Sonnet 4.6 significantly improves resistance to prompt injection attacks during computer use — a critical safety consideration for production deployments. The model operates under ASL-3 safety protocols.

Should You Migrate from Opus?

This is the question we are evaluating for our own infrastructure. Claude Sonnet 4.6 We run Claude Opus 4.6 across 15 cron jobs handling content creation, social media engagement, SEO optimization, and autonomous monitoring. Here is our framework for the migration decision:

Migrate to Sonnet 4.6 when:

• The task is primarily coding or agentic tool use
• Cost reduction matters more than marginal quality gains
• You need the same 1M token context window at lower cost
• The workload involves computer use or office automation

Stay on Opus 4.6 when:

• Extended thinking on complex reasoning tasks is critical
• You need the highest possible instruction-following fidelity
• Creative writing quality is the primary concern
• The cost difference is negligible relative to the value produced

For many production workloads, Sonnet 4.6 is likely sufficient. The 79.6% SWE-bench score matches or exceeds what Opus 4.5 achieved, and the pricing makes high-volume agentic workflows economically viable for the first time.

Real-World Cost Savings Analysis

To make this concrete, consider a typical AI-powered development workflow. A team running 50 agent sessions per day, each consuming approximately 100K tokens in input and 20K tokens in output, would face these monthly costs:

• On Opus 4.6: 150M input tokens × $15/M + 30M output tokens × $75/M = $2,250 + $2,250 = $4,500/month
• On Sonnet 4.6: 150M input tokens × $3/M + 30M output tokens × $15/M = $450 + $450 = $900/month

That is $3,600 per month in savings — or $43,200 annually — with minimal performance degradation for coding-focused workloads. For organizations running hundreds of agent sessions, the savings reach six figures.

The 1M token context window in beta adds another dimension. Previously, teams needing extended context had no choice but Opus 4.6. Sonnet 4.6 removes that lock-in, making long-document analysis, large codebase comprehension, and multi-file refactoring accessible at Sonnet pricing.

According to The New Stack, enterprises are already evaluating migration plans, particularly for agentic coding pipelines where Sonnet 4.6's SWE-bench performance makes it a direct Opus replacement.

What Sonnet 4.6 Does Not Replace

It is important to be precise about the limitations. While Sonnet 4.6 approaches Opus performance in structured, benchmark-measurable tasks, Opus 4.6 retains advantages in several areas:

• Extended thinking depth: For multi-step reasoning chains requiring 10+ minutes of deliberation, Opus still produces more thorough analysis
• Nuanced instruction following: Tasks requiring precise adherence to complex, multi-constraint prompts still favor Opus
• Creative writing quality: For marketing copy, long-form narratives, and style-sensitive content, the quality gap remains noticeable
• Novel problem domains: Opus shows stronger generalization on tasks outside standard benchmark distributions

The Reddit community has noted one specific concern: "benchmarks are great but model doesn't want to talk." Some users report that Sonnet 4.6 can feel more task-oriented and less conversational than Opus, which may matter for user-facing chat applications.

The Competitive Landscape

Sonnet 4.6 does not exist in a vacuum. The same week, Alibaba released Qwen 3.5 — a 397-billion parameter open-weight model under Apache 2.0 that challenges closed-model pricing economics entirely. GitHub has already made Sonnet 4.6 generally available in Copilot.

The broader trend is clear: flagship-level AI performance is commoditizing rapidly. What cost $15/$75 per million tokens six months ago now costs $3/$15 — or potentially nothing with open-weight alternatives. Development teams that locked into expensive model tiers should reassess their architecture.

Safety and Deployment

Anthropic deployed Sonnet 4.6 under its ASL-3 safety level. According to the system card, safety researchers concluded the model has "a broadly warm, honest, prosocial, and at times funny character, very strong safety behaviors, and no signs of major concerns around high-stakes forms of misalignment."

The model also shows improved prompt injection resistance compared to Sonnet 4.5, performing similarly to Opus 4.6 on safety benchmarks. This matters particularly for computer use deployments where the model interacts with untrusted web content.

Frequently Asked Questions

How much does Claude Sonnet 4.6 cost?

Claude Sonnet 4.6 costs $3 per million input tokens and $15 per million output tokens — the same pricing as Sonnet 4.5 and one-fifth the cost of Opus 4.6.

Is Claude Sonnet 4.6 better than Opus?

Sonnet 4.6 matches or exceeds Opus 4.5 on most benchmarks and approaches Opus 4.6 performance in coding and computer use tasks. Opus 4.6 retains an edge in complex reasoning and extended thinking.

What is Claude Sonnet 4.6's context window?

Sonnet 4.6 features a 1M token context window in beta, matching the capacity of Opus 4.6. Standard context is 200K tokens.

Can I use Claude Sonnet 4.6 for free?

Claude Sonnet 4.6 is the default model for free-tier users on claude.ai and Claude Cowork, with usage limits that reset every five hours.

How does Sonnet 4.6 compare to GPT-5.2?

Sonnet 4.6 outperforms GPT-5.2 on agentic financial analysis, office tasks, and computer use benchmarks, while costing roughly one-third the price at the API level.

What is SWE-bench Verified?

SWE-bench Verified is a benchmark that tests AI models on resolving real GitHub issues. Sonnet 4.6 scores 79.6%, the highest among mid-tier models as of February 2026.