Model Comparison

Claude Opus 5 vs o1-previewWhich is better in 2026?

Comparing Claude Opus 5 and o1-preview across benchmarks, pricing, and capabilities.

Verdict: Claude Opus 5 vs o1-preview — which is better?

Claude Opus 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.

On price, Claude Opus 5 is roughly 2.6x cheaper per token on a blended 3:1 input/output basis, which adds up quickly at production volume.

Claude Opus 5 also accepts a larger context window (1,000,000 input tokens), making it the stronger choice for long documents and large codebases.

Choose Claude Opus 5 if…

  • cost matters — it's about 2.6x cheaper per token
  • you process long inputs — it offers a 1,000,000 token context window
  • you want the most recent training data — it shipped Jul 2026

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

No common benchmarks found

Claude Opus 5 and o1-previewdon'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 Opus 5 costs less

For input processing, Claude Opus 5 ($5.00/1M tokens) is 3.0x cheaper than o1-preview ($15.00/1M tokens).

For output processing, Claude Opus 5 ($25.00/1M tokens) is 2.4x cheaper than o1-preview ($60.00/1M tokens).

In conclusion, o1-preview is more expensive than Claude Opus 5.*

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

Lowest available price from all providers
Sat Jul 25 2026 • llm-stats.com
Anthropic
Claude Opus 5
Input tokens$5.00
Output tokens$25.00
Best providerAnthropic
OpenAI
o1-preview
Input tokens$15.00
Output tokens$60.00
Best providerOpenAI
Notice missing or incorrect data?Start an Issue→

Context Window

Maximum input and output token capacity

Claude Opus 5 accepts 1,000,000 input tokens compared to o1-preview's 128,000 tokens. Claude Opus 5 can generate longer responses up to 128,000 tokens, while o1-preview is limited to 32,768 tokens.

Anthropic
Claude Opus 5
Input1,000,000 tokens
Output128,000 tokens
OpenAI
o1-preview
Input128,000 tokens
Output32,768 tokens
Sat Jul 25 2026 • llm-stats.com

Input Capabilities

Supported data types and modalities

Claude Opus 5 supports multimodal inputs, whereas o1-preview does not.

Claude Opus 5 can handle both text and other forms of data like images, making it suitable for multimodal applications.

Claude Opus 5

Text
Images
Audio
Video

o1-preview

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 5

Proprietary

Closed source

o1-preview

Proprietary

Closed source

Release Timeline

When each model was launched

Claude Opus 5 was released on 2026-07-24, while o1-preview was released on 2024-09-12.

Claude Opus 5 is 23 months newer than o1-preview.

Claude Opus 5

Jul 24, 2026

0 days ago

1.9yr newer
o1-preview

Sep 12, 2024

1.9 years ago

Knowledge Cutoff

When training data ends

Neither model specifies a knowledge cutoff date.

Unable to compare the recency of their training data.

No cutoff dates available

Provider Availability

Claude Opus 5 is available from Anthropic. o1-preview is available from OpenAI, Azure.

Claude Opus 5

anthropic logo
Anthropic
Input Price:Input: $5.00/1MOutput Price:Output: $25.00/1M

o1-preview

openai logo
OpenAI
Input Price:Input: $15.00/1MOutput Price:Output: $60.00/1M
azure logo
Azure
Input Price:Input: $16.50/1MOutput Price:Output: $66.00/1M
* Prices shown are per million tokens

Outputs Comparison

Notice missing or incorrect data?Start an Issue discussion→

Key Takeaways

Anthropic
Larger context window (1,000,000 tokens)
Supports multimodal inputs
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 Opus 5 and o1-preview side-by-side, then vote on the output you prefer.

Claude Opus 5
✓ Preferred
o1-preview
Open in Playground
AI Model Comparison Table
Feature
Anthropic
Claude Opus 5
OpenAI
o1-preview

FAQ

Common questions about Claude Opus 5 vs o1-preview.

Which is better, Claude Opus 5 or o1-preview?

Claude Opus 5 (Anthropic) and o1-preview (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 Opus 5 compare to o1-preview in benchmarks?

Claude Opus 5 scores BrowseComp: 90.8%, BioMysteryBench: 90.1%, OSWorld 2.0: 70.6%, DeepSWE 1.1: 68.8%, Humanity's Last Exam: 64.7%. o1-preview scores MGSM: 90.8%, MMLU: 90.8%, MATH: 85.5%, GPQA: 73.3%, LiveBench: 52.3%.

Is Claude Opus 5 cheaper than o1-preview?

Claude Opus 5 is 3.0x cheaper for input tokens. Claude Opus 5 costs $5.00/M input and $25.00/M output via anthropic. o1-preview costs $15.00/M input and $60.00/M output via openai.

What are the context window sizes for Claude Opus 5 and o1-preview?

Claude Opus 5 supports 1.0M tokens and o1-preview supports 128K tokens. A larger context window lets you process longer documents, conversations, or codebases in a single request.

What are the main differences between Claude Opus 5 and o1-preview?

Key differences include context window (1.0M vs 128K), input pricing ($5.00 vs $15.00/M), multimodal support (yes vs no). See the full comparison above for benchmark-by-benchmark results.

Who makes Claude Opus 5 and o1-preview?

Claude Opus 5 is developed by Anthropic and o1-preview is developed by OpenAI.

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