GPT-4o mini vs GPT OSS 120B
GPT OSS 120B significantly outperforms across most benchmarks. GPT OSS 120B is 1.5x cheaper per token.
OpenAI · OpenAI · Updated for 2026
Which is better?
GPT-4o mini outperforms in 0 benchmarks, while GPT OSS 120B is better at 2 benchmarks (GPQA, MMLU). GPT OSS 120B significantly outperforms across most benchmarks.
On price, GPT OSS 120B is roughly 1.5x cheaper per token on a blended 3:1 input/output basis, which adds up quickly at production volume.
GPT OSS 120B also accepts a larger context window (131,072 input tokens), making it the stronger choice for long documents and large codebases.
Based on current benchmark, pricing, and model metadata for 2026.
Choose GPT-4o mini
- you want predictable pricing at $0.15/M input and $0.60/M output
Choose GPT OSS 120B
- you want the strongest raw capability — it leads on 2 of 2 shared benchmarks
- cost matters — it's about 1.5x cheaper per token
- you process long inputs — it offers a 131,072 token context window
- you want the most recent training data — it shipped Aug 2025
- you need open weights you can self-host or fine-tune
At a glance
The differences that matter most.
Performance Benchmarks
Comparative analysis across standard metrics
GPT-4o mini outperforms in 0 benchmarks, while GPT OSS 120B is better at 2 benchmarks (GPQA, MMLU).
GPT OSS 120B significantly outperforms across most benchmarks.
Arena Performance
Playground indexes and blind preference scores
Pricing Analysis
Price comparison per million tokens
For input processing, GPT-4o mini ($0.15/1M tokens) is 1.7x more expensive than GPT OSS 120B ($0.09/1M tokens).
For output processing, GPT-4o mini ($0.60/1M tokens) is 1.3x more expensive than GPT OSS 120B ($0.45/1M tokens).
In conclusion, GPT-4o mini is more expensive than GPT OSS 120B.*
* Using a 3:1 ratio of input to output tokens
Context Window
Maximum input and output token capacity
GPT OSS 120B accepts 131,072 input tokens compared to GPT-4o mini's 128,000 tokens. GPT OSS 120B can generate longer responses up to 131,072 tokens, while GPT-4o mini is limited to 16,384 tokens.
Input Capabilities
Supported data types and modalities
GPT-4o mini supports multimodal inputs, whereas GPT OSS 120B does not.
GPT-4o mini can handle both text and other forms of data like images, making it suitable for multimodal applications.
GPT-4o mini
GPT OSS 120B
License
Usage and distribution terms
GPT-4o mini is licensed under a proprietary license, while GPT OSS 120B uses Apache 2.0.
License differences may affect how you can use these models in commercial or open-source projects.
Proprietary
Closed source
Apache 2.0
Open weights
Release Timeline
When each model was launched
GPT-4o mini was released on 2024-07-18, while GPT OSS 120B was released on 2025-08-05.
GPT OSS 120B is 13 months newer than GPT-4o mini.
Jul 18, 2024
2.1 years ago
Aug 5, 2025
1.1 years ago
1.0yr newerKnowledge Cutoff
When training data ends
GPT-4o mini has a documented knowledge cutoff of 2023-10-01, while GPT OSS 120B's cutoff date is not specified.
We can confirm GPT-4o mini's training data extends to 2023-10-01, but cannot make a direct comparison without GPT OSS 120B's cutoff date.
Oct 2023
—
Provider Availability
GPT-4o mini is available from Azure. GPT OSS 120B is available from DeepInfra, Novita, OpenAI, Fireworks, Groq.
GPT-4o mini
GPT OSS 120B
Outputs Comparison
Judge for yourself.
Run your own prompts against GPT-4o mini and GPT OSS 120B side-by-side, then vote on the output you prefer.
FAQ
Common questions about GPT-4o mini vs GPT OSS 120B.