Model Comparison
GPT-5 nano vs o3-proWhich is better in 2026?
Comparing GPT-5 nano and o3-pro across benchmarks, pricing, and capabilities.
Verdict: GPT-5 nano vs o3-pro — which is better?
GPT-5 nano (by OpenAI) 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, GPT-5 nano is roughly 254.5x cheaper per token on a blended 3:1 input/output basis, which adds up quickly at production volume.
GPT-5 nano also accepts a larger context window (400,000 input tokens), making it the stronger choice for long documents and large codebases.
Choose GPT-5 nano if…
- cost matters — it's about 254.5x cheaper per token
- you process long inputs — it offers a 400,000 token context window
- you want the most recent training data — it shipped Aug 2025
Choose o3-pro if…
- you want predictable pricing at $20.00/M input and $80.00/M output
Performance Benchmarks
Comparative analysis across standard metrics
GPT-5 nano 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
For input processing, GPT-5 nano ($0.05/1M tokens) is 400.0x cheaper than o3-pro ($20.00/1M tokens).
For output processing, GPT-5 nano ($0.40/1M tokens) is 200.0x cheaper than o3-pro ($80.00/1M tokens).
In conclusion, o3-pro is more expensive than GPT-5 nano.*
* Using a 3:1 ratio of input to output tokens
Context Window
Maximum input and output token capacity
GPT-5 nano accepts 400,000 input tokens compared to o3-pro's 200,000 tokens. GPT-5 nano can generate longer responses up to 128,000 tokens, while o3-pro is limited to 100,000 tokens.
Input Capabilities
Supported data types and modalities
Both GPT-5 nano and o3-pro support multimodal inputs.
They are both capable of processing various types of data, offering versatility in application.
GPT-5 nano
o3-pro
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
GPT-5 nano was released on 2025-08-07, while o3-pro was released on 2025-06-10.
GPT-5 nano is 2 months newer than o3-pro.
Aug 7, 2025
11 months ago
1mo newerJun 10, 2025
1.1 years ago
Knowledge Cutoff
When training data ends
GPT-5 nano has a knowledge cutoff of 2024-05-30, while o3-pro has a cutoff of 2024-05-31.
o3-pro has more recent training data (up to 2024-05-31), making it potentially better informed about events through that date compared to GPT-5 nano (2024-05-30).
May 2024
May 2024
Provider Availability
GPT-5 nano is available from OpenAI. o3-pro is available from OpenAI.
GPT-5 nano
o3-pro
Outputs Comparison
Key Takeaways
GPT-5 nano
View detailsOpenAI
o3-pro
View detailsOpenAI
No standout differentiators in the data we have for this pair.
Detailed Comparison
Interactive Arena
Judge for yourself.
Run your own prompts against GPT-5 nano and o3-pro side-by-side, then vote on the output you prefer.
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FAQ
Common questions about GPT-5 nano vs o3-pro.