AnthropicClaude Sonnet 4.5

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Claude Sonnet 4.5 is an Anthropic Claude model for reasoning, coding, multimodal analysis, and tool-using agents.

Token context
200K tokens
Inputs
Text, Image
Outputs
Text
Released
Sep 29, 2025

Providers & Pricing

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ProviderInput / 1MOutput / 1MCache read / 1MCache write / 1MObservedEvidence
$3.00$15.00$0.30Sep 3, 2026Provider-reported
ARC-AGI-1verified-v1-15fb467fd4fc63.67percentClaude Sonnet 4.5 (Thinking 32K)unknownOriginal sourcewinner eligibleThird-party benchmark
ARC-AGI-2verified-v2-9a3db289984e13.61percentClaude Sonnet 4.5 (Thinking 32K)unknownOriginal sourcewinner eligibleThird-party benchmark
Berkeley Function Calling Leaderboardv4-ede5081a24bc73.24percentClaude-Sonnet-4-5-20250929 (FC)unknownRecomputedwinner eligibleThird-party benchmark
Berkeley Function Calling Leaderboardv4-ede5081a24bc24.90percentClaude-Sonnet-4-5-20250929 (Prompt)unknownRecomputedwinner eligibleThird-party benchmark
LMArena Document Arenadocument-2026-07-30-0115087206961,446.19rating28,634claude-sonnet-4-5-20250929; 95% CI [1439.60004073, 1452.78970477]; votes 28634; rank 22unknownOriginal sourcewinner eligibleThird-party benchmark
LMArena Search Arenasearch-2026-08-24-0115087206961,158.46rating127,378claude-sonnet-4-5-search; 95% CI [1153.41447529, 1163.49714967]; votes 127378; rank 24unknownOriginal sourcewinner eligibleThird-party benchmark
LMArena Text Arenatext-2026-09-01-0115087206961,438.27rating79,668claude-sonnet-4-5-20250929; 95% CI [1435.36635364, 1441.17549670]; votes 79668; rank 66unknownOriginal sourcewinner eligibleThird-party benchmark
LMArena Text Arenatext-2026-09-01-0115087206961,433.95rating81,031claude-sonnet-4-5-20250929-high-32k; 95% CI [1431.13754052, 1436.75329939]; votes 81031; rank 79unknownOriginal sourcewinner eligibleThird-party benchmark
ToneBench2026-08-28-10-task-cd9819ab6e4d77.25points2,44150Claude Sonnet 4.5average per caseOriginal sourcewinner eligibleThird-party benchmark

At a Glance

Model Facts

Identity

Status
active
Developer ID
claude-sonnet-4-5
Released
Sep 29, 2025
Version
Claude Sonnet 4.5
License
Unknown

Capacity

Token context
200K tokens
Maximum output
64K tokens
Total parameters
Unknown
Active parameters
Unknown
Knowledge cutoff
Jan 1, 2025

Interface and Access

Inputs
Text, Image
Outputs
Text
API available
Yes
Open weights
No
Self-hostable
No
Reasoning
Yes
Vision
Yes
Tool calling
Yes
Capabilities
chat, generation, reasoning, structured outputs, tools

This page represents one developer model product. Dated API snapshots, serving endpoints, pricing, regions, quantizations, and service tiers attach as versioned aliases or provider details and never create duplicate public model records.

Version Lineage

PredecessorUnknown
SuccessorsUnknown
Aliasesclaude-sonnet-4-5, claude-sonnet-4-5-20250929

Explicit Unknowns

  • Architecture
  • Tokenizer

Primary Evidence

Sources and Observation Date

Comparable Peers

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Questions

Claude Sonnet 4.5 FAQs

What is Claude Sonnet 4.5?+

Claude Sonnet 4.5 is an Anthropic Claude model for reasoning, coding, multimodal analysis, and tool-using agents. It is developed by Anthropic and its current sourced lifecycle status is active.

What inputs and outputs does Claude Sonnet 4.5 support?+

Claude Sonnet 4.5's current record lists Text and Image as input and Text as output.

How much context does Claude Sonnet 4.5 support?+

The current record lists a 200K-token context window and a maximum output of 64K tokens.

Is Claude Sonnet 4.5 available through an API?+

Claude Sonnet 4.5 is marked as API-available. The directly sourced provider records currently include Anthropic.

How much does Claude Sonnet 4.5 cost through an API?+

The lowest directly sourced prices currently attached to Claude Sonnet 4.5 are $3.00 per million input tokens through Anthropic and $15.00 per million output tokens through Anthropic. Prices are provider-specific and should be checked against each cited observation date.

What capabilities and tasks does Claude Sonnet 4.5 support?+

Claude Sonnet 4.5's recorded capabilities are chat, generation, reasoning, structured outputs, and tools. Its supported tasks are image, reasoning, and text.

Can Claude Sonnet 4.5 be self-hosted?+

Claude Sonnet 4.5 is not marked as an open-weight model. Self-hosting is marked as unsupported, with no license recorded.

Does Claude Sonnet 4.5 have related versions or aliases?+

No predecessor is recorded. No successor is recorded. Recorded aliases are claude-sonnet-4-5 and claude-sonnet-4-5-20250929.

Which models can Claude Sonnet 4.5 be compared with?+

The current compatible peer set includes GPT-6 Astra, Claude Fable 5.1, Gemini 3.1 Pro, DeepSeek V4 Pro, and Grok 4.6. Compatibility requires shared sourced modalities and tasks; it does not imply that one model is better. Browse model comparisons

How current is the Model Markets record for Claude Sonnet 4.5?+

Claude Sonnet 4.5 was last verified Sep 3, 2026 from Anthropic's primary source, “Claude Sonnet 4.5 | Claude Platform Docs.” The evidence is classified as official fact.

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