Model Comparison

Claude Sonnet 4 vs Claude Sonnet 4.5Which is better in 2026?

Claude Sonnet 4.5 significantly outperforms across most benchmarks. Claude Sonnet 4 and Claude Sonnet 4.5 cost the same.

Verdict: Claude Sonnet 4 vs Claude Sonnet 4.5 — which is better?

Claude Sonnet 4 (by Anthropic) and Claude Sonnet 4.5 (by Anthropic) are two of the AI models people compare most. Here is how they stack up on benchmarks, price and capabilities, and which one to pick in 2026.

Claude Sonnet 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.

Choose Claude Sonnet 4 if…

  • you want predictable pricing at $3.00/M input and $15.00/M output

Choose Claude Sonnet 4.5 if…

  • you want the strongest raw capability — it leads on 6 of 6 shared benchmarks
  • you want the most recent training data — it shipped Sep 2025
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Performance Benchmarks

Comparative analysis across standard metrics

6 benchmarks

Claude Sonnet 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.

Fri Jun 12 2026 • llm-stats.com

Arena Performance

Human preference votes

Pricing Analysis

Price comparison per million tokens

For input processing, Claude Sonnet 4 ($3.00/1M tokens) costs the same as Claude Sonnet 4.5 ($3.00/1M tokens).

For output processing, Claude Sonnet 4 ($15.00/1M tokens) costs the same as Claude Sonnet 4.5 ($15.00/1M tokens).

In conclusion, Claude Sonnet 4 and Claude Sonnet 4.5 cost the same.*

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

Lowest available price from all providers
Fri Jun 12 2026 • llm-stats.com
Anthropic
Claude Sonnet 4
Input tokens$3.00
Output tokens$15.00
Best providerAnthropic
Anthropic
Claude Sonnet 4.5
Input tokens$3.00
Output tokens$15.00
Best providerAnthropic
Notice missing or incorrect data?Start an Issue→

Context Window

Maximum input and output token capacity

Both models have the same input context window of 200,000 tokens. Both models can generate responses up to 64,000 tokens.

Anthropic
Claude Sonnet 4
Input200,000 tokens
Output64,000 tokens
Anthropic
Claude Sonnet 4.5
Input200,000 tokens
Output64,000 tokens
Fri Jun 12 2026 • llm-stats.com

Input Capabilities

Supported data types and modalities

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

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

Claude Sonnet 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 Sonnet 4

Proprietary

Closed source

Claude Sonnet 4.5

Proprietary

Closed source

Release Timeline

When each model was launched

Claude Sonnet 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 Sonnet 4.

Claude Sonnet 4

May 22, 2025

1.1 years ago

Claude Sonnet 4.5

Sep 29, 2025

8 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 Sonnet 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 Sonnet 4's cutoff date.

Claude Sonnet 4

—

Claude Sonnet 4.5

Jan 2025

Provider Availability

Claude Sonnet 4 is available from Anthropic, Bedrock, Google. Claude Sonnet 4.5 is available from Anthropic.

Claude Sonnet 4

anthropic logo
Anthropic
Input Price:Input: $3.00/1MOutput Price:Output: $15.00/1M
bedrock logo
AWS Bedrock
Input Price:Input: $3.00/1MOutput Price:Output: $15.00/1M
google logo
Google
Input Price:Input: $3.00/1MOutput Price:Output: $15.00/1M

Claude Sonnet 4.5

anthropic logo
Anthropic
Input Price:Input: $3.00/1MOutput Price:Output: $15.00/1M
* Prices shown are per million tokens

Outputs Comparison

Notice missing or incorrect data?Start an Issue discussion→

Key Takeaways

Anthropic

No standout differentiators in the data we have for this pair.

Anthropic
Higher AIME 2025 score (87.0% vs 70.5%)
Higher GPQA score (83.4% vs 75.4%)
Higher MMMLU score (89.1% vs 86.5%)
Higher TAU-bench Airline score (70.0% vs 60.0%)
Higher TAU-bench Retail score (86.2% vs 80.5%)
Higher Terminal-Bench score (50.0% vs 35.5%)
AnthropicClaude Sonnet 4
AnthropicClaude Sonnet 4.5
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Detailed Comparison

AI Model Comparison Table
Feature
Anthropic
Claude Sonnet 4
Anthropic
Claude Sonnet 4.5

FAQ

Common questions about Claude Sonnet 4 vs Claude Sonnet 4.5.

Which is better, Claude Sonnet 4 or Claude Sonnet 4.5?

Claude Sonnet 4.5 significantly outperforms across most benchmarks. Claude Sonnet 4 is made by Anthropic and Claude Sonnet 4.5 is made by Anthropic. The best choice depends on your use case — compare their benchmark scores, pricing, and capabilities above.

How does Claude Sonnet 4 compare to Claude Sonnet 4.5 in benchmarks?

Claude Sonnet 4 scores MMMLU: 86.5%, TAU-bench Retail: 80.5%, GPQA: 75.4%, MMMU: 74.4%, SWE-Bench Verified: 72.7%. Claude Sonnet 4.5 scores MMMLU: 89.1%, AIME 2025: 87.0%, TAU-bench Retail: 86.2%, GPQA: 83.4%, MMMUval: 77.8%.

Is Claude Sonnet 4 cheaper than Claude Sonnet 4.5?

Both models cost $3.00 per million input tokens.

What are the context window sizes for Claude Sonnet 4 and Claude Sonnet 4.5?

Claude Sonnet 4 supports 200K tokens and Claude Sonnet 4.5 supports 200K tokens. A larger context window lets you process longer documents, conversations, or codebases in a single request.

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