Decoding OpenAI’s Model Naming & How to Purchase Them

OpenAI models follow a clear, four-part naming convention. Understanding it will help you pick the right model for your application—whether you need a chat assistant, a deep-reasoning engine, or a multimodal powerhouse.

🤖 1. Model Naming Convention

Copy 
Series – Model – Parameter Scale – Reasoning Intensity
  • Series
    • GPT = general chat models
  • Model
    • (no prefix) → basic chat
    • o1, o3, o4 → enhanced reasoning
    • 4o (suffix) → multimodal (text + vision)
  • Parameter Scale
    • nano = smallest / fastest / cheapest
    • mini = lightweight / low-compute
    • pro = full capacity / best performance
  • Reasoning Intensity
    • low = minimal “thinking,” most efficient
    • medium = balanced
    • high = deep reasoning, higher compute

Example:
GPT-4o-pro-high
A multimodal (4o) model with Pro-level parameters and High reasoning intensity.

🔍 2. Model Categories at a Glance

Category Naming Example Primary Use Case
Chat GPT-3.5-turbo General chat & Q&A
Reasoning o3-mini-medium Complex problem-solving, “thoughtful”
Multimodal GPT-4o Text + image understanding & generation

📏 3. Scale & Intensity Trade-Offs

Scale Description
nano Tiny footprint → lowest latency & cost
mini Light compute → fast & affordable
pro Maximum capacity → top performance
Intensity Description
low Quick responses, minimal context review
medium Balanced reasoning vs. efficiency
high Deep “thinking,” longer runtimes

💳 4. How to Purchase & Access

Model Access Path Input Price (per 1 M tokens) Output Price (per 1 M tokens) Notes
gpt-3.5-turbo ChatGPT Free & Plus; API $2.00 $4.00 Included in ChatGPT Plus subscription
gpt-4 (8K) ChatGPT Plus; API $30.00 $60.00 8,192-token context window
gpt-4-32k API $60.00 $120.00 32,768-token context window
gpt-4.1-pro-high API $3.00 $12.00 Enhanced reasoning variant; fine-tuning available
gpt-4o API $5.00 $20.00 Multimodal: text + image
gpt-4o-mini API $0.60 $2.40 Lightweight multimodal
gpt-4.5 ChatGPT Pro & API preview $75.00 — Next-gen reasoning, limited preview

Notes:

  • Prices are approximate; check the OpenAI pricing page for updates.
  • A token ≈ 4 characters of input or output text.
  • API billing is strictly pay-as-you-go—no monthly minimums.

🚀 5. Getting Started

  1. Sign up at platform.openai.com.
  2. Generate an API key in your dashboard.
  3. Choose your model in the request payload:
    json Copy 
    {
  "model": "gpt-4o-pro-high",
  "messages": [...]
}
  4. Monitor usage & costs via the console.

🔧 6. GPU Testing & Fine-Tuning

If you need GPU resources to test and fine-tune your code, try NiceGPU. It provides scalable, pay-as-you-go GPU access—perfect for experimentation and model training.

With these insights, you can confidently select the right OpenAI model—balancing cost, performance, and capabilities—tailored to your project’s needs. Happy building! 🎉