AI Model Watch
Models / Anthropic

Claude Sonnet 4.5

Deprecated

API ID claude-sonnet-4-5-20250929 (alias claude-sonnet-4-5). DEPRECATED: Anthropic's deprecations page states 'On September 30, 2026, Anthropic notified developers using Claude Sonnet 4.5 of its upcoming retirement on the Claude API', with retirement date November 30, 2026 and recommended replacement claude-sonnet-5-5; the model-status table reads Deprecated / September 30, 2026 / November 30, 2026. Signal used: that table, read first-hand 2026-10-02 after check-lifecycle-drift reported the status flip. Until 2026-10-02 the row read ga: the table said Active with a tentative retirement not sooner than September 29, 2026, and the overview listed the model under Legacy models. Still priced: $3 in / $15 out per MTok; extended thinking: Yes; adaptive thinking: No. 200k context, max output 64k. 5m cache $3.75, 1h cache $6, cache hits $0.30/MTok. Batch $1.50/$7.50. Reliable knowledge cutoff Jan 2025; training data cutoff Jul 2025. Snapshot 20250929 implies a Sep 29, 2025 release, but Anthropic publishes no explicit release date on the overview, so released stays null.

Claude Sonnet 4.5 by Anthropic costs $3 per 1M input tokens and $15 per 1M output tokens ($6/1M blended), with a 200K (200.000-token) context window. It is deprecated, shutting down 30 Nov 2026; the recommended replacement is Claude Sonnet 5.5.

Last verified: 24 Oct 2026 · sourced from official provider documentation

Retires on 30 Nov 2026 · deprecated since 30 Sep 2026

Lifecycle warning

This model is deprecated. Recommended migration: Claude Sonnet 5.5.

Read the Claude Sonnet 4.5 migration guide → replacement & cheapest alternatives

Provider
Anthropic
Status
Deprecated
Input price
$3 / 1M tokens
Output price
$15 / 1M tokens
Cached input
$0.3 / 1M tokens
Blended price
$6 / 1M tokens
Context window
200.000 tokens (200K)
Max output
64.000 tokens
Modality
text, image, vision
Open weights
No — API only
Knowledge cutoff
2025-01
Released
—
API string
claude-sonnet-4-5-20250929

Source: Anthropic official documentation ↗

See also

Explore more

All Anthropic models→

Prices, context windows and lifecycle status for every Anthropic model we track.

Compare models head-to-head→

Side-by-side price, context and status for the models developers weigh against each other.

FAQ

Claude Sonnet 4.5 — questions & answers

How much does Claude Sonnet 4.5 cost?

Claude Sonnet 4.5 is priced at $3 per 1M input tokens and $15 per 1M output tokens ($6/1M blended at a 3:1 input-to-output ratio), with cached input at $0.3 per 1M tokens.

What is the context window of Claude Sonnet 4.5?

Claude Sonnet 4.5 has a 200.000-token context window (200K), with up to 64.000 output tokens per request.

Is Claude Sonnet 4.5 being deprecated or retired?

Claude Sonnet 4.5 is deprecated. Its scheduled shutdown date is 30 Nov 2026. The recommended migration is Claude Sonnet 5.5.

Does Claude Sonnet 4.5 support image or vision input?

Yes — Claude Sonnet 4.5 accepts image input. Listed modalities: text, image, vision.

Can I self-host Claude Sonnet 4.5?

No — Claude Sonnet 4.5 is proprietary. Its weights are not publicly released, so it is available only through Anthropic's API (or hosted partners), not for self-hosting.

What is the API model string for Claude Sonnet 4.5?

The API model identifier for Claude Sonnet 4.5 is "claude-sonnet-4-5-20250929" when calling Anthropic's API.

What is Claude Sonnet 4.5's knowledge cutoff?

Claude Sonnet 4.5's training knowledge cutoff is Jan 2025.