Model Comparison

Claude Sonnet 4.5 vs o3

Claude Sonnet 4.5 significantly outperforms across most benchmarks. o3 is 1.7x cheaper per token.

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Performance Benchmarks

Comparative analysis across standard metrics

2 benchmarks

Claude Sonnet 4.5 outperforms in 2 benchmarks (AIME 2025, GPQA), while o3 is better at 0 benchmarks.

Claude Sonnet 4.5 significantly outperforms across most benchmarks.

Thu May 14 2026 • llm-stats.com

Arena Performance

Human preference votes

Pricing Analysis

Price comparison per million tokens

o3 costs less

For input processing, Claude Sonnet 4.5 ($3.00/1M tokens) is 1.5x more expensive than o3 ($2.00/1M tokens).

For output processing, Claude Sonnet 4.5 ($15.00/1M tokens) is 1.9x more expensive than o3 ($8.00/1M tokens).

In conclusion, Claude Sonnet 4.5 is more expensive than o3.*

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

Lowest available price from all providers
Thu May 14 2026 • llm-stats.com
Anthropic
Claude Sonnet 4.5
Input tokens$3.00
Output tokens$15.00
Best providerAnthropic
OpenAI
o3
Input tokens$2.00
Output tokens$8.00
Best providerOpenAI
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. o3 can generate longer responses up to 100,000 tokens, while Claude Sonnet 4.5 is limited to 64,000 tokens.

Anthropic
Claude Sonnet 4.5
Input200,000 tokens
Output64,000 tokens
OpenAI
o3
Input200,000 tokens
Output100,000 tokens
Thu May 14 2026 • llm-stats.com

Input Capabilities

Supported data types and modalities

Both Claude Sonnet 4.5 and o3 support multimodal inputs.

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

Claude Sonnet 4.5

Text
Images
Audio
Video

o3

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 4.5

Proprietary

Closed source

o3

Proprietary

Closed source

Release Timeline

When each model was launched

Claude Sonnet 4.5 was released on 2025-09-29, while o3 was released on 2025-04-16.

Claude Sonnet 4.5 is 6 months newer than o3.

Claude Sonnet 4.5

Sep 29, 2025

7 months ago

5mo newer
o3

Apr 16, 2025

1.1 years ago

Knowledge Cutoff

When training data ends

Claude Sonnet 4.5 has a knowledge cutoff of 2025-01-31, while o3 has a cutoff of 2024-05-31.

Claude Sonnet 4.5 has more recent training data (up to 2025-01-31), making it potentially better informed about events through that date compared to o3 (2024-05-31).

Claude Sonnet 4.5

Jan 2025

8 mo newer
o3

May 2024

Provider Availability

Claude Sonnet 4.5 is available from Anthropic. o3 is available from OpenAI.

Claude Sonnet 4.5

anthropic logo
Anthropic
Input Price:Input: $3.00/1MOutput Price:Output: $15.00/1M

o3

openai logo
OpenAI
Input Price:Input: $2.00/1MOutput Price:Output: $8.00/1M
* Prices shown are per million tokens

Outputs Comparison

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Key Takeaways

Anthropic
Higher AIME 2025 score (87.0% vs 86.4%)
Higher GPQA score (83.4% vs 83.3%)
OpenAI
Less expensive input tokens
Less expensive output tokens
AnthropicClaude Sonnet 4.5
OpenAIo3
Compare in Playground

Detailed Comparison

AI Model Comparison Table
Feature
Anthropic
Claude Sonnet 4.5
OpenAI
o3

FAQ

Common questions about Claude Sonnet 4.5 vs o3.

Which is better, Claude Sonnet 4.5 or o3?

Claude Sonnet 4.5 significantly outperforms across most benchmarks. Claude Sonnet 4.5 is made by Anthropic and o3 is made by OpenAI. The best choice depends on your use case — compare their benchmark scores, pricing, and capabilities above.

How does Claude Sonnet 4.5 compare to o3 in benchmarks?

Claude Sonnet 4.5 scores MMMLU: 89.1%, AIME 2025: 87.0%, TAU-bench Retail: 86.2%, GPQA: 83.4%, MMMUval: 77.8%. o3 scores COLLIE: 98.4%, AIME 2024: 91.6%, ARC-AGI: 88.0%, MathVista: 86.8%, AIME 2025: 86.4%.

Is Claude Sonnet 4.5 cheaper than o3?

o3 is 1.5x cheaper for input tokens. Claude Sonnet 4.5 costs $3.00/M input and $15.00/M output via anthropic. o3 costs $2.00/M input and $8.00/M output via openai.

What are the context window sizes for Claude Sonnet 4.5 and o3?

Claude Sonnet 4.5 supports 200K tokens and o3 supports 200K tokens. A larger context window lets you process longer documents, conversations, or codebases in a single request.

What are the main differences between Claude Sonnet 4.5 and o3?

Key differences include input pricing ($3.00 vs $2.00/M). See the full comparison above for benchmark-by-benchmark results.

Who makes Claude Sonnet 4.5 and o3?

Claude Sonnet 4.5 is developed by Anthropic and o3 is developed by OpenAI.