Model Comparison

Claude 3 Sonnet vs o3-proWhich is better in 2026?

Comparing Claude 3 Sonnet and o3-pro across benchmarks, pricing, and capabilities.

Verdict: Claude 3 Sonnet vs o3-pro — which is better?

Claude 3 Sonnet (by Anthropic) and o3-pro (by OpenAI) 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.

On price, Claude 3 Sonnet is roughly 5.8x cheaper per token on a blended 3:1 input/output basis, which adds up quickly at production volume.

Choose Claude 3 Sonnet if…

  • cost matters — it's about 5.8x cheaper per token

Choose o3-pro if…

  • you want the most recent training data — it shipped Jun 2025

Performance Benchmarks

Comparative analysis across standard metrics

No common benchmarks found

Claude 3 Sonnet and o3-prodon't have any common benchmark datasets to compare. They may have been evaluated on different testing suites.

Arena Performance

Human preference votes

Pricing Analysis

Price comparison per million tokens

Claude 3 Sonnet costs less

For input processing, Claude 3 Sonnet ($3.00/1M tokens) is 6.7x cheaper than o3-pro ($20.00/1M tokens).

For output processing, Claude 3 Sonnet ($15.00/1M tokens) is 5.3x cheaper than o3-pro ($80.00/1M tokens).

In conclusion, o3-pro is more expensive than Claude 3 Sonnet.*

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

Lowest available price from all providers
Sat Jun 27 2026 • llm-stats.com
Anthropic
Claude 3 Sonnet
Input tokens$3.00
Output tokens$15.00
Best providerAnthropic
OpenAI
o3-pro
Input tokens$20.00
Output tokens$80.00
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. Claude 3 Sonnet can generate longer responses up to 200,000 tokens, while o3-pro is limited to 100,000 tokens.

Anthropic
Claude 3 Sonnet
Input200,000 tokens
Output200,000 tokens
OpenAI
o3-pro
Input200,000 tokens
Output100,000 tokens
Sat Jun 27 2026 • llm-stats.com

Input Capabilities

Supported data types and modalities

Both Claude 3 Sonnet and o3-pro support multimodal inputs.

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

Claude 3 Sonnet

Text
Images
Audio
Video

o3-pro

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 3 Sonnet

Proprietary

Closed source

o3-pro

Proprietary

Closed source

Release Timeline

When each model was launched

Claude 3 Sonnet was released on 2024-02-29, while o3-pro was released on 2025-06-10.

o3-pro is 16 months newer than Claude 3 Sonnet.

Claude 3 Sonnet

Feb 29, 2024

2.3 years ago

o3-pro

Jun 10, 2025

1.0 years ago

1.3yr newer

Knowledge Cutoff

When training data ends

o3-pro has a documented knowledge cutoff of 2024-05-31, while Claude 3 Sonnet's cutoff date is not specified.

We can confirm o3-pro's training data extends to 2024-05-31, but cannot make a direct comparison without Claude 3 Sonnet's cutoff date.

Claude 3 Sonnet

—

o3-pro

May 2024

Provider Availability

Claude 3 Sonnet is available from Anthropic, Bedrock, Google. o3-pro is available from OpenAI.

Claude 3 Sonnet

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

o3-pro

openai logo
OpenAI
Input Price:Input: $20.00/1MOutput Price:Output: $80.00/1M
* Prices shown are per million tokens

Outputs Comparison

Notice missing or incorrect data?Start an Issue discussion→

Key Takeaways

Anthropic
Less expensive input tokens
Less expensive output tokens
OpenAI

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

Detailed Comparison

Interactive Arena

Judge for yourself.

Run your own prompts against Claude 3 Sonnet and o3-pro side-by-side, then vote on the output you prefer.

Claude 3 Sonnet
✓ Preferred
o3-pro
Open in Playground
AI Model Comparison Table
Feature
Anthropic
Claude 3 Sonnet
OpenAI
o3-pro

FAQ

Common questions about Claude 3 Sonnet vs o3-pro.

Which is better, Claude 3 Sonnet or o3-pro?

Claude 3 Sonnet (Anthropic) and o3-pro (OpenAI) each have strengths in different areas. Compare their benchmark scores, pricing, context windows, and capabilities above to determine which fits your needs.

How does Claude 3 Sonnet compare to o3-pro in benchmarks?

Claude 3 Sonnet scores ARC-C: 93.2%, GSM8k: 92.3%, HellaSwag: 89.0%, MGSM: 83.5%, BIG-Bench Hard: 82.9%.

Is Claude 3 Sonnet cheaper than o3-pro?

Claude 3 Sonnet is 6.7x cheaper for input tokens. Claude 3 Sonnet costs $3.00/M input and $15.00/M output via anthropic. o3-pro costs $20.00/M input and $80.00/M output via openai.

What are the context window sizes for Claude 3 Sonnet and o3-pro?

Claude 3 Sonnet supports 200K tokens and o3-pro 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 3 Sonnet and o3-pro?

Key differences include input pricing ($3.00 vs $20.00/M). See the full comparison above for benchmark-by-benchmark results.

Who makes Claude 3 Sonnet and o3-pro?

Claude 3 Sonnet is developed by Anthropic and o3-pro is developed by OpenAI.

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