Claude Opus 4 vs Claude Sonnet 4.5 Comparison

Comparing Claude Opus 4 and Claude Sonnet 4.5 across benchmarks, pricing, and capabilities.

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Performance Benchmarks

Comparative analysis across standard metrics

6 benchmarks

Claude Opus 4 outperforms in 0 benchmarks, while Claude Sonnet 4.5 is better at 6 benchmarks (AIME 2025, GPQA, MMMLU, TAU-bench Airline, TAU-bench Retail, Terminal-Bench).

Claude Sonnet 4.5 significantly outperforms across most benchmarks.

Sat Mar 14 2026 • llm-stats.com

Arena Performance

Human preference votes

Pricing Analysis

Price comparison per million tokens

Claude Sonnet 4.5 costs less

For input processing, Claude Opus 4 ($15.00/1M tokens) is 5.0x more expensive than Claude Sonnet 4.5 ($3.00/1M tokens).

For output processing, Claude Opus 4 ($75.00/1M tokens) is 5.0x more expensive than Claude Sonnet 4.5 ($15.00/1M tokens).

In conclusion, Claude Opus 4 is more expensive than Claude Sonnet 4.5.*

* Using a 3:1 ratio of input to output tokens

Lowest available price from all providers

Sat Mar 14 2026 • llm-stats.com

Claude Opus 4

Input tokens$15.00

Output tokens$75.00

Best providerAnthropic

Claude Sonnet 4.5

Input tokens$3.00

Output tokens$15.00

Best providerAnthropic

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Context Window

Maximum input and output token capacity

Both models have the same input context window of 200,000 tokens. Claude Sonnet 4.5 can generate longer responses up to 64,000 tokens, while Claude Opus 4 is limited to 32,000 tokens.

Claude Opus 4

Input200,000 tokens

Output32,000 tokens

Claude Sonnet 4.5

Input200,000 tokens

Output64,000 tokens

Sat Mar 14 2026 • llm-stats.com

Input Capabilities

Supported data types and modalities

Both Claude Opus 4 and Claude Sonnet 4.5 support multimodal inputs.

They are both capable of processing various types of data, offering versatility in application.

Claude Opus 4

Text

Images

Audio

Video

Claude Sonnet 4.5

Text

Images

Audio

Video

License

Usage and distribution terms

Both models are licensed under proprietary licenses.

Both models have usage restrictions defined by their respective organizations.

Claude Opus 4

Proprietary

Closed source

Claude Sonnet 4.5

Proprietary

Closed source

Release Timeline

When each model was launched

Claude Opus 4 was released on 2025-05-22, while Claude Sonnet 4.5 was released on 2025-09-29.

Claude Sonnet 4.5 is 4 months newer than Claude Opus 4.

Claude Opus 4

May 22, 2025

9 months ago

Claude Sonnet 4.5

Sep 29, 2025

5 months ago

4mo newer

Knowledge Cutoff

When training data ends

Claude Sonnet 4.5 has a documented knowledge cutoff of 2025-01-31, while Claude Opus 4's cutoff date is not specified.

We can confirm Claude Sonnet 4.5's training data extends to 2025-01-31, but cannot make a direct comparison without Claude Opus 4's cutoff date.

Claude Opus 4

—

Claude Sonnet 4.5

Jan 2025

Provider Availability

Claude Opus 4 is available from Anthropic, Bedrock, Google. Claude Sonnet 4.5 is available from Anthropic. The availability of providers can affect quality of the model and reliability.