Model Comparison
Claude Sonnet 4.5 vs o1-previewWhich is better in 2026?
Claude Sonnet 4.5 significantly outperforms across most benchmarks. Claude Sonnet 4.5 is 4.4x cheaper per token.
Verdict: Claude Sonnet 4.5 vs o1-preview — which is better?
Claude Sonnet 4.5 (by Anthropic) and o1-preview (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.
Claude Sonnet 4.5 outperforms in 1 benchmarks (GPQA), while o1-preview is better at 0 benchmarks. Claude Sonnet 4.5 significantly outperforms across most benchmarks.
On price, Claude Sonnet 4.5 is roughly 4.4x cheaper per token on a blended 3:1 input/output basis, which adds up quickly at production volume.
Claude Sonnet 4.5 also accepts a larger context window (200,000 input tokens), making it the stronger choice for long documents and large codebases.
Choose Claude Sonnet 4.5 if…
- you want the strongest raw capability — it leads on 1 of 1 shared benchmarks
- cost matters — it's about 4.4x cheaper per token
- you process long inputs — it offers a 200,000 token context window
- you want the most recent training data — it shipped Sep 2025
Choose o1-preview if…
- you want predictable pricing at $15.00/M input and $60.00/M output
Performance Benchmarks
Comparative analysis across standard metrics
Claude Sonnet 4.5 outperforms in 1 benchmarks (GPQA), while o1-preview is better at 0 benchmarks.
Claude Sonnet 4.5 significantly outperforms across most benchmarks.
Arena Performance
Human preference votes
Pricing Analysis
Price comparison per million tokens
For input processing, Claude Sonnet 4.5 ($3.00/1M tokens) is 5.0x cheaper than o1-preview ($15.00/1M tokens).
For output processing, Claude Sonnet 4.5 ($15.00/1M tokens) is 4.0x cheaper than o1-preview ($60.00/1M tokens).
In conclusion, o1-preview is more expensive than Claude Sonnet 4.5.*
* Using a 3:1 ratio of input to output tokens
Context Window
Maximum input and output token capacity
Claude Sonnet 4.5 accepts 200,000 input tokens compared to o1-preview's 128,000 tokens. Claude Sonnet 4.5 can generate longer responses up to 64,000 tokens, while o1-preview is limited to 32,768 tokens.
Input Capabilities
Supported data types and modalities
Claude Sonnet 4.5 supports multimodal inputs, whereas o1-preview does not.
Claude Sonnet 4.5 can handle both text and other forms of data like images, making it suitable for multimodal applications.
Claude Sonnet 4.5
o1-preview
License
Usage and distribution terms
Both models are licensed under proprietary licenses.
Both models have usage restrictions defined by their respective organizations.
Proprietary
Closed source
Proprietary
Closed source
Release Timeline
When each model was launched
Claude Sonnet 4.5 was released on 2025-09-29, while o1-preview was released on 2024-09-12.
Claude Sonnet 4.5 is 13 months newer than o1-preview.
Sep 29, 2025
8 months ago
1.0yr newerSep 12, 2024
1.8 years ago
Knowledge Cutoff
When training data ends
Claude Sonnet 4.5 has a documented knowledge cutoff of 2025-01-31, while o1-preview'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 o1-preview's cutoff date.
Jan 2025
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Provider Availability
Claude Sonnet 4.5 is available from Anthropic. o1-preview is available from OpenAI, Azure.
Claude Sonnet 4.5
o1-preview
Outputs Comparison
Key Takeaways
Claude Sonnet 4.5
View detailsAnthropic
o1-preview
View detailsOpenAI
No standout differentiators in the data we have for this pair.
Detailed Comparison
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FAQ
Common questions about Claude Sonnet 4.5 vs o1-preview.