GPT-5 Codex vs gpt-oss-120b (Comparative Analysis)
Loading comparison form...
Comparative Analysis: GPT-5 Codex vs. gpt-oss-120b
Want to try out these models side by side?Try Magica for free
Overview
gpt-oss-120b was released 1 month before GPT-5 Codex.
 GPT-5 Codex | gpt-oss-120b | |
|---|---|---|
Model Provider The organization behind this AI's development | OpenAI | OpenAI |
Input Context Window Maximum input tokens this model can process at once | 400K tokens | 131.1K tokens |
Output Token Limit Maximum output tokens this model can generate at once | 128K tokens | 131.1K tokens |
Release Date When this model first became publicly available | September 23, 2025 10 months ago September 23rd, 2025 | August 5, 2025 11 months ago August 5th, 2025 |
Knowledge Cutoff Latest training-data date reported by the provider | September 30, 2024 | June 30, 2024 |
Capabilities & Features
Compare supported features, modalities, and advanced capabilities
GPT-5 Codex | gpt-oss-120b | |
|---|---|---|
Input Types Supported input formats | 📝Text🖼️Image | 📝Text |
Reasoning Controls Defaults and configurable reasoning effort | Always enabled | Always enabledEffort: High, Medium, LowDefault: Medium |
Output Types Supported output formats | 📝Text | 📝Text |
Tokenizer Text encoding system | GPT | GPT |
Key Features Advanced capabilities | ✓Function Calling✓Structured Output✓Reasoning Mode✓Content Moderation | ✓Function Calling✓Structured Output✓Reasoning ModeContent Moderation |
Open Source Model availability | Proprietary | Available on HuggingFace → |
Pricing
GPT-5 Codex is roughly 31.3x more expensive compared to gpt-oss-120b for input tokens and roughly 58.8x more expensive for output tokens.
| GPT-5 Codex | gpt-oss-120b | |
|---|---|---|
Input Token Cost Cost per million input tokens | $1.25 per million tokens | $0.04 per million tokens |
Output Token Cost Cost per million output tokens | $10.00 per million tokens | $0.17 per million tokens |
Web Search Cost Additional cost for each web search operation | $0.01 per search | Not specified |
Cache Read Cost Cost to reuse cached input tokens | $0.13 per million tokens | Not specified |
Benchmarks
Compare relevant benchmarks between GPT-5 Codex and gpt-oss-120b.
| GPT-5 Codex | gpt-oss-120b | |
|---|---|---|
Intelligence Index Overall model quality across independent evaluations | Benchmark not available. | 23.8 (Artificial Analysis index; higher is better) |
Coding Index Programming performance across independent evaluations | Benchmark not available. | 30.4 (Artificial Analysis index; higher is better) |
Agentic Index Ability to complete multi-step agentic tasks | Benchmark not available. | 13.2 (Artificial Analysis index; higher is better) |
Best Design Arena Score Highest human-preference Elo score across design arenas | 1,138 Elo (#26 in Webapps (52.4% win rate)) | 1,050 Elo (#91 in Game Dev (40.6% win rate)) |
At a Glance
Quick overview of what makes GPT-5 Codex and gpt-oss-120b unique.
GPT-5 Codex by OpenAI understands both text and images, can use external tools and APIs, offers advanced reasoning, generates structured data. It can handle standard conversations with its 400K token context window. Reasonably priced at $1.25/M input and $10.00/M output tokens. Includes built-in content moderation for safer outputs. Released September 23rd, 2025.gpt-oss-120b by OpenAI can use external tools and APIs, offers advanced reasoning, generates structured data. It can handle standard conversations with its 131.1K token context window. Very affordable at $0.04/M input and $0.17/M output tokens. Released August 5th, 2025.Explore More Comparisons
Compare your models with top performers across different categories
Compare GPT-5 Codex with:
🚀Programming
Best models for coding and development
🎨Creative & Roleplay
Models optimized for creative writing
📢Marketing
Content creation and marketing tasks
💻Technology
Technical analysis and explanations
🔬Science
Scientific research and analysis
🌐Translation
Multilingual translation tasks
Compare gpt-oss-120b with:
🚀Programming
Best models for coding and development
🎨Creative & Roleplay
Models optimized for creative writing
📢Marketing
Content creation and marketing tasks
💻Technology
Technical analysis and explanations
🔬Science
Scientific research and analysis
🌐Translation
Multilingual translation tasks