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Claude Sonnet 4.5 vs Claude Sonnet 5.5

Claude Sonnet 5.5: 77.6% average across five Vision Evals tasks (#14 of 69 models). We have not run Claude Sonnet 4.5 through Roboflow's Vision Evals, so there is no head-to-head score. Run both on your own image below.

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AnthropicClaude Sonnet 4.5
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AnthropicClaude Sonnet 5.5
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Claude Sonnet 4.5 vs Claude Sonnet 5.5 Comparison Table

Evals updated November 12, 2026Pricing updated November 13, 2026

PropertyClaude Sonnet 4.5Claude Sonnet 5.5
OrganizationAnthropicAnthropic
Categoryclosedclosed
Modalitymultimodalmultimodal
Release DateSep 2025Sep 2026
Context Window200K1.0M
ParametersUnknownUnknown
LicenseProprietaryProprietary
Commercial usecommercial use per vendor termscommercial use per vendor terms
Pricing per 1M tokens
Input $/1M$3.00$2.00
Output $/1M$15.00$10.00
Vision Tasks
Both support 10 more tasks
Model Features
Both support 3 more features
Vision Evalsground-truth scores across 5 vision tasks, pooled at low effort
OverallNot evaluated
77.6%
Avg cost / sample–$0.0073
Avg speed / sample–8.33s
By task
Object Detection (low)–
74.3%
±0.9, Mean of 3 runs, range 73.5 to 75.3
$0.0098
Object Detection (high)–
76.8%
±0.4, Mean of 3 runs, range 76.5 to 77.3
$0.014
Counting (low)–
79.3%
±0.7, Mean of 3 runs, range 78.4 to 79.7
$0.0042
Counting (high)–
82.9%
±1.4, Mean of 3 runs, range 81.1 to 83.8
$0.0053
Identification (low)–
91.7%
±3.1, Mean of 3 runs, range 87.5 to 93.8
$0.0029
Identification (high)–
90.6%
±0.0, Mean of 3 runs, range 90.6 to 90.6
$0.0033
OCR–
66.3%
$0.0075
by category
Single value
48.7%
Transcription
76.3%
Structured JSON
83.8%
Text localization
60.6%
Reasoning (low)–
76.4%
±0.7, Mean of 3 runs, range 75.5 to 76.8
$0.0049
Reasoning (high)–
83.9%
±1.7, Mean of 3 runs, range 82.1 to 85.4
$0.0061

Claude Sonnet 4.5 vs Claude Sonnet 5.5: Overview

Claude Sonnet 4.5

Claude Sonnet 4.5, released by Anthropic in September 2025, is the company’s most advanced Sonnet-series model, built for high-performance reasoning, coding, and long-horizon agentic workflows. It is a multimodal system that accepts both text and images, with a 200,000-token context window designed for handling large documents and extended interactions. Anthropic highlights its improvements in reliability, reduced sycophancy, and alignment, making it suitable for sustained enterprise use.

It introduces infrastructure features such as a memory tool (beta), checkpointing for Claude Code, parallel tool use, and tighter integration with VS Code. Compared to Opus, which targets broader reasoning, Sonnet 4.5 is optimized for structured, long-duration tasks. Positioned against leading offerings from OpenAI and Google, it is aimed at enterprise automation, software engineering, and research-intensive applications.

Claude Sonnet 5.5

Claude Sonnet 5.5 is a proprietary multimodal language model from Anthropic and the second release in the Claude 5.5 family, following Claude Opus 5.5. It accepts interleaved text and image input and returns text, operating with a 1M token context window and a maximum output of 128K tokens per request. The model uses adaptive thinking by default, allocating variable reasoning effort per request rather than exposing a manual extended thinking toggle, and its training data cutoff is June 2026. Anthropic positions it as a faster, lower cost complement to Opus 5.5 for well scoped everyday tasks, bug fixing, and producing documents, slides, and spreadsheets.

Anthropic describes it as the first Sonnet model able to complete Pokemon Red from screenshots alone, and it generates output more than 30% faster than Sonnet 5 while using fewer tokens for equivalent work.