Model Comparison
GPT-5 mini vs o3Which is better in 2026?
GPT-5 mini shows notably better performance in the majority of benchmarks. GPT-5 mini is 5.1x cheaper per token.
Verdict: GPT-5 mini vs o3 — which is better?
GPT-5 mini (by OpenAI) and o3 (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.
GPT-5 mini outperforms in 3 benchmarks (AIME 2025, FrontierMath, Humanity's Last Exam), while o3 is better at 1 benchmark (GPQA). GPT-5 mini shows notably better performance in the majority of benchmarks.
On price, GPT-5 mini is roughly 5.1x cheaper per token on a blended 3:1 input/output basis, which adds up quickly at production volume.
GPT-5 mini also accepts a larger context window (400,000 input tokens), making it the stronger choice for long documents and large codebases.
Choose GPT-5 mini if…
- you want the strongest raw capability — it leads on 3 of 4 shared benchmarks
- cost matters — it's about 5.1x 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 if…
- you want predictable pricing at $2.00/M input and $8.00/M output
Performance Benchmarks
Comparative analysis across standard metrics
GPT-5 mini outperforms in 3 benchmarks (AIME 2025, FrontierMath, Humanity's Last Exam), while o3 is better at 1 benchmark (GPQA).
GPT-5 mini shows notably better performance in the majority of benchmarks.
Arena Performance
Human preference votes
Pricing Analysis
Price comparison per million tokens
For input processing, GPT-5 mini ($0.25/1M tokens) is 8.0x cheaper than o3 ($2.00/1M tokens).
For output processing, GPT-5 mini ($2.00/1M tokens) is 4.0x cheaper than o3 ($8.00/1M tokens).
In conclusion, o3 is more expensive than GPT-5 mini.*
* Using a 3:1 ratio of input to output tokens
Context Window
Maximum input and output token capacity
GPT-5 mini accepts 400,000 input tokens compared to o3's 200,000 tokens. GPT-5 mini can generate longer responses up to 128,000 tokens, while o3 is limited to 100,000 tokens.
Input Capabilities
Supported data types and modalities
Both GPT-5 mini and o3 support multimodal inputs.
They are both capable of processing various types of data, offering versatility in application.
GPT-5 mini
o3
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 mini was released on 2025-08-07, while o3 was released on 2025-04-16.
GPT-5 mini is 4 months newer than o3.
Aug 7, 2025
11 months ago
3mo newerApr 16, 2025
1.3 years ago
Knowledge Cutoff
When training data ends
GPT-5 mini has a knowledge cutoff of 2024-05-30, while o3 has a cutoff of 2024-05-31.
o3 has more recent training data (up to 2024-05-31), making it potentially better informed about events through that date compared to GPT-5 mini (2024-05-30).
May 2024
May 2024
Provider Availability
GPT-5 mini is available from OpenAI. o3 is available from OpenAI.
GPT-5 mini
o3
Outputs Comparison
Key Takeaways
GPT-5 mini
View detailsOpenAI
o3
View detailsOpenAI
GPT-5 minio3Detailed Comparison
Interactive Arena
Judge for yourself.
Run your own prompts against GPT-5 mini and o3 side-by-side, then vote on the output you prefer.
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FAQ
Common questions about GPT-5 mini vs o3.