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Claude Sonnet 4.5

API ID claude-sonnet-4-5-20250929

claude-sonnet-4-5-20250929 is an Anthropic model, released September 2025. It has a 200,000-token context window and up to 64,000 output tokens. It takes image input and supports reasoning. Standard price: $3.00 input and $15.00 output per 1M tokens.

Status
Deprecated
Released
September 2025
Shutdown
Nov 30, 2026

It stops serving on November 30, 2026. Recommended replacement: claude-sonnet-5-5.

How to migrate to Claude Sonnet 5.5

Benchmarks

Scores as each source published them
or

Comparing with Claude Sonnet 4 (2025-05-14), the previous model in this line. A score is compared only with the same benchmark from the same source, at the same setting where both have it. Full comparison: prices, limits, features

Arena

ArenaClaude Sonnet 4.5Claude Sonnet 4 (2025-05-14)ChangeRankDateSource
Text
Other settings
  • 1455 ±3 vs 1391 ±4
By category
  • Math 1455 rank 70 vs 1404 (+51) at high effort 32k (vs thinking 32k)
  • Creative writing 1450 rank 38 vs 1396 (+54) at high effort 32k (vs thinking 32k)
  • Instruction following 1464 rank 46 vs 1416 (+48) at high effort 32k (vs thinking 32k)
  • Hard prompts 1487 rank 55 vs 1433 (+54) at high effort 32k (vs thinking 32k)
  • Long prompts 1486 rank 35 vs 1443 (+43) at high effort 32k (vs thinking 32k)
  • Multi-turn 1472 rank 55 vs 1421 (+51) at high effort 32k (vs thinking 32k)
  • Expert 1498 rank 47 vs 1434 (+64) at high effort 32k (vs thinking 32k)
1456 ±31402 ±4+5466 of 415
83,948 votes		Oct 13, 2026source
Text: Coding
Other settings
  • 1512 ±5 vs 1449 ±7
1519 ±51474 ±8+4537 of 410
19,953 votes		Oct 13, 2026source
WebDev
Other settings
  • 1385 ±7 vs not rated
1393 ±8not rated95 of 142
13,253 votes		Oct 13, 2026source
Search1176 ±5not rated31 of 42
144,153 votes		Oct 13, 2026source
Document1449 ±6not rated33 of 44
31,455 votes		Sep 13, 2026source

Rated as claude-sonnet-4-5-20250929-high-32k (high effort 32k); Claude Sonnet 4 (2025-05-14) as claude-sonnet-4-20250514-thinking-32k. Some were rated at different settings; ratings on one arena share one scale, so the difference still reads directly. Ratings come from people voting between two anonymous answers; Text, Search and Document are style-controlled, as on arena.ai. Not rated on Vision, where Claude Sonnet 4 (2025-05-14) is. Data: Arena (arena.ai), CC BY 4.0.

Epoch AI

BenchmarkClaude Sonnet 4.5Claude Sonnet 4 (2025-05-14)ChangeSettingRunSource
FrontierMath Tier 42.4%not run32kJun 11, 2026source
FrontierMath Tiers 1-323.9%not run32kJun 11, 2026source
GPQA Diamond
Other settings
  • 81.7% vs 78.3% 32k
  • 78.8% vs 75.8% 16k
  • 73.7% vs 66.7%
82.3%79.2%+3.1 pts59kOct 28, 2025source
MATH Level 597.7%84.4%+13.3 pts32k (vs no setting)Oct 21, 2025source
OTIS Mock AIME 2024-2025
Other settings
  • 77.8% vs 71.1% 32k
  • 71.1% vs 53.3% 16k
  • 35.6% vs 28.9%
77.8%68.9%+8.9 pts59kOct 28, 2025source
SimpleQA Verified
Other settings
  • 23.7% vs not run
30.7%not run59kAug 27, 2026source
SWE-bench Verified71.3%not runFeb 5, 2026source

Run independently by Epoch AI. Data: Epoch AI, Capabilities & benchmarking (epoch.ai/benchmarks), CC BY.

On cloud platforms

All platform dates
PlatformPlatform IDStateShutdownTime leftReplacementSource
Amazon Bedrockanthropic.claude-sonnet-4-5-20250929-v1:0LegacyApr 8, 2027175 days—source
Microsoft Foundryversion 1claude-sonnet-4-5ActiveNov 30, 202646 daysClaude Sonnet 5.5claude-sonnet-5-5source

Amazon Bedrock retires this model 129 days after Anthropic's own API.

Microsoft Foundry (version 1) retires this model on the same day as Anthropic's own API.

Read daily from each platform's own pages. The shutdown date and countdown on this page use Anthropic's own date. Time left counts to 00:00 UTC on the shutdown date, which is the evening before in ET.

Aliases pointing here: claude-sonnet-4-5 (in place when tracking began (October 6, 2026))

Features

Compare models
FeatureValueSinceSource
Prompt cachingA prompt prefix you send again and again (system prompt, documents, tools) is cached, so later requests cost less and start faster.Supportedin place when tracking began (October 6, 2026)source
Batch APISend many requests as one job that runs in the background, usually finished within 24 hours, at a lower price than live requests.Supportedin place when tracking began (October 6, 2026)source
Image inputImages such as screenshots, photos and charts can go in the prompt for the model to read.Supportedin place when tracking began (October 6, 2026)source
Reasoning / thinkingThe model can work through a problem step by step before it answers: usually better answers to hard questions, at the cost of more tokens and time.Supported (thinking: extended; effort: not supported)in place when tracking began (October 6, 2026)source
Context windowThe most the model can work with in one request, in tokens: your prompt, conversation history and files. A token is about three-quarters of an English word.200,000 tokensin place when tracking began (October 6, 2026)source
Max output tokensThe longest reply the model can write in one response, in tokens. A token is about three-quarters of an English word.64,000 tokensin place when tracking began (October 6, 2026)source

Not published by Anthropic: Structured outputs, Function calling, PDF input, Fine-tuning, Built-in web search, temperature parameter, top_p parameter, logprobs.

Price history

USD per 1M tokens, standard tier
$0.00$5.00$10.00$15.00$20.00Oct 2026In $3.00Out $15.00Oct 1, 2026 to Oct 15, 2026: Input $3.00, Output $15.00
$0.00$5.00$10.00$15.00$20.00Oct 2026In $3.00Out $15.00Oct 1, 2026 to Oct 15, 2026: Input $3.00, Output $15.00

We started recording this model's prices on Oct 1, 2026. The history grows with each daily check.

Show as a table
FromTypePrice
Oct 1, 2026Input$3.00
Oct 1, 2026Output$15.00

Prices

USD per 1M tokens, every type and band, by tier
TypePrice $/1MIn effect
Standard
input$3.00
cached input$0.30
cache write (5 min)$3.75
cache write (1 hour)$6.00
output$15.00
Batch
input$1.50
output$7.50

Changelog

Changes we detected on Anthropic's pages
  1. Platform date changed

    Amazon Bedrock moved the shutdown date for claude-sonnet-4-5-20250929 from not before Sep 30, 2026 to Apr 8, 2027

    Info

Related news

Time until shutdown
45days
11hours
24min
20sec

Counting to 7:00 pm ET on November 29, 2026, which is 00:00 UTC on November 30, 2026.

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Last checked · Sources: Anthropic models, Anthropic deprecations, Anthropic pricing, Anthropic model pages