Claude Sonnet 5

by Anthropic

Claude Sonnet 5 is a model from Anthropic, released on June 30, 2026. It has a 1M-token context window and can generate up to 64K output tokens. API pricing is $2 per 1M input tokens and $10 per 1M output tokens. It ranks #26 of 220 models by Intelligence Score with a score of 47.2.

Claude Sonnet 5 is Anthropic's most agentic Sonnet-class model, an upgrade to Sonnet 4.6 that narrows the gap to Opus 4.8 on reasoning, tool use, coding, computer use, and knowledge work while staying lower priced. It plans, uses tools like browsers and terminals, and runs autonomously for long-horizon tasks. Capability gains include SWE-Bench Verified (85.2%), SWE-Bench Pro (63.2%), SWE-Bench Multilingual (78.3%), Terminal-Bench 2.1 (80.4%), OSWorld-Verified (81.2%), BrowseComp (84.7% single-agent, 86.6% multi-agent), Humanity's Last Exam with tools (57.4%), USAMO 2026 (79.5%), GDPval-AA v2 (1618 Elo), HealthBench Professional (57.8%), and FrontierCode v1 (38.8%). It supports adaptive thinking with selectable effort levels up to 'extra high' (xhigh) and a 1M-token context window with context compaction. The safety assessment found lower rates of misaligned behavior, hallucination, and sycophancy than Sonnet 4.6, with improved prompt-injection robustness; it ships with cyber safeguards enabled by default and uses an updated tokenizer (input maps to roughly 1.0-1.35x more tokens than Sonnet 4.6). Default model on Free and Pro plans and available to Max, Team, and Enterprise users, in Claude Code, and on the Claude Platform. Launches with introductory pricing of $2/$10 per million input/output tokens through August 31, 2026, then $3/$15. Available via the Claude API as `claude-sonnet-5`.

Key specs

ProviderAnthropic
Release date2026-06-30
Licenseproprietary
Context window1M tokens
Max output64K tokens
Input price$2 / 1M tokens
Output price$10 / 1M tokens
Intelligence Score47.2
Coding index34.8

Quick answers

What is the context window of Claude Sonnet 5?

Claude Sonnet 5 has a context window of 1M tokens, with a maximum output of 64K tokens per response.

How much does Claude Sonnet 5 cost?

Claude Sonnet 5 costs $2 per 1M input tokens and $10 per 1M output tokens through the API.

Is Claude Sonnet 5 open source?

No. Claude Sonnet 5 is a proprietary model from Anthropic (proprietary license).

When was Claude Sonnet 5 released?

Anthropic released Claude Sonnet 5 on June 30, 2026.

How does Claude Sonnet 5 compare to Claude Opus 5.5 (Reasoning)?

Claude Sonnet 5 scores 47.2 on the Intelligence Score versus 60.5 for Claude Opus 5.5 (Reasoning), the current #1. Input pricing is $2 vs $4 per 1M tokens.

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