Anthropic Claude Sonnet 4.6 — what it is, when to use it and what to use instead

Summary

Claude Sonnet 4.6 is the previous Sonnet release, at $3 per million input tokens and $15 per million output tokens with a 1M-token context window. Its successor, Claude Sonnet 5, is both newer and cheaper at $2 / $10.

Sonnet 4.6 was released on 17 February 2026 and was superseded by Claude Sonnet 5 on 30 June 2026. The two share the same 1M-token context window and 128K max output, but Sonnet 5 costs a third less per token and moves the reliable knowledge cutoff from August 2025 to January 2026. There is no cost argument for staying.

It accepts text and image input and returns text, with adaptive thinking and effort defaulting to high; the manual extended-thinking mode is deprecated on this model and returns a 400 error on Sonnet 5.

No deprecation has been announced. Anthropic commits to keeping Claude Sonnet 4.6 available until at least 17 February 2027.

Modality

• Text
• Vision

Use case

• Chat
• Coding
• Reasoning
• Agents & tool use
• Long context

Tier

• Mid-tier

Access

• Hosted API

Languages

• Multilingual

Specifications

Input price

$3.00 / M tokens

Output price

$15.00 / M tokens

Price band

Premium

Context window

1M tokens

Max output

128K tokens

Input

Text, image

Output

Text

Knowledge cutoff

August 2025

Tool use

Yes

Structured output

Yes

Weights licence

not published

Model maker

Anthropic

“unknown” means the figure has not been published, or we have not verified it yet — never that the answer is no. “not published” under the weights licence means this model is not offered with downloadable weights. The price band is ours: it bands the blended price (three parts input to one part output) as budget (≤ $0.50), standard (≤ $3), premium (≤ $12) or flagship.

Lifecycle

Anthropic has not announced a deprecation or shutdown date for this model. That is a statement about what has been published, not a guarantee — providers typically announce a shutdown months ahead, and this page updates when they do.

1. Released 17 February 2026
2. Deprecated not announced
3. Retired not announced

Use it for

• Keep an existing Sonnet 4.6 integration running while you evaluate Claude Sonnet 5 against it.
• Stay on a fixed model during a release freeze, then migrate in one step.

Avoid it when

• You are starting a new integration; Claude Sonnet 5 is newer and costs $2 / $10 against $3 / $15 here.
• Your code uses manual extended thinking, which is deprecated here and rejected on Sonnet 5, so the migration will need work either way.
• You need knowledge of events after August 2025, which is where this model's reliable cutoff sits.

Alternatives to consider

• Claude Sonnet 5 Curated

  Anthropic ● Active

  The successor: same 1M-token window, cheaper at $2 / $10 against $3 / $15, and a January 2026 knowledge cutoff.

  $2.00 in · $10.00 out / M tokens · 1M context

• Claude Haiku 4.5 Curated

  Anthropic ● Active

  A third of the price at $1 / $5 if your workload is high volume and fits a 200K-token window.

  $1.00 in · $5.00 out / M tokens · 200K context

• GPT-5.6 Terra Curated

  OpenAI ● Active

  OpenAI's balanced tier at $2 / $12 with a 1.05M-token context window and a February 2026 knowledge cutoff.

  $2.00 in · $12.00 out / M tokens · 1.1M context

• Gemini 3.6 Flash Curated

  Google (Gemini) ● Active

  Google's balanced tier at $0.75 / $3.75, a quarter of the input price, with audio, video and PDF input.

  $0.75 in · $3.75 out / M tokens · 1M context

• Claude Sonnet 4.5 Derived

  Amazon Bedrock ● Active

  Alternative from Amazon Bedrock, same tier (mid-tier), similar price; shares chat, coding, reasoning, agents and long-context.

  $3.00 in · $15.00 out / M tokens · 200K context

Curated suggestions were picked by a reviewer, with the reason written by hand. Derived suggestions are ranked from the data — shared tags, the same tier and a comparable price band — not from benchmark scores. Check the capability fit yourself: we track lifecycle, price and specifications.

Sources

• platform.claude.com ↗ https://platform.claude.com/docs/en/models/sonnet-4-6/overview
• platform.claude.com ↗ https://platform.claude.com/docs/en/about-claude/pricing
• platform.claude.com ↗ https://platform.claude.com/docs/en/about-claude/models/overview
• platform.claude.com ↗ https://platform.claude.com/docs/en/about-claude/model-deprecations

Verified against the source on 10 September 2026. Dataset snapshot 10 September 2026. Providers can change a date without notice — the link above is always the final word.

About this profile

The specifications and dates above are facts from Anthropic, with the sources listed. The summary, the use-for and avoid-when lists and the curated alternatives are our assessment: editorial profile reviewed on 21 September 2026 by llm-researcher.