ChatGPT 4o vs o3: what really changes between the two active models in 2025

The two models coexist on the platform, but with different roles and distinct performance.

GPT-4o is the visible model for free and Plus users, while o3 (for Pro) and o3-pro (for Enterprise) operate both in the background and as selectable options for users.

As of July 2025, the ChatGPT platform includes several models from the GPT-4 family, but the ones effectively used in the web app and consumer versions are mainly two: GPT-4o and OpenAI o3 (including the enhanced o3-pro variant). GPT-4o is the default model for most users, both free and Plus, while o3 is used in specific backend contexts, API environments, or infrastructural fallback—and is also regularly selectable through the user interface on both app and web. Although they belong to the same architectural generation, the operational and performance differences are especially noticeable in everyday usage.

O3 is for Pro users and o3-pro can be used only by Enterprise plan users.

GPT-4o is faster, smoother, and multimodal, with superior responsiveness on complex prompts.

The “omni” version handles text, visual, and voice input with a unified engine, reducing latency times.

According to benchmarks published by Data Studios, GPT-4o responds significantly faster than o3 and o3-pro, with latency averaging 35% lower on multi-turn prompts. The real innovation of the “omni” model is the unification of multimodal capabilities: GPT-4o natively handles text, image, and audio input, offering a natural transition between different channels without the need for separate modules. This makes it ideal for the user experience on ChatGPT mobile, desktop, and browser, where fluidity and immediacy are essential. The o3 model, on the other hand, is focused on pure text and requires external routing for any visual or voice functionality.

Structured task performance remains solid with o3, especially in professional and deterministic contexts.

The o3-pro model is optimized for stable loads, greater predictability, and intensive API usage.

Although GPT-4o is more advanced in terms of multimodality and interactivity, the o3-pro model still maintains advantages in response consistency, low-temperature stability, and predictable handling of classic functions. This makes it still preferred in environments where excessive creativity must be avoided, such as AI-assisted editorial workflows, custom business tools, or critical automations. Additionally, o3-pro is lighter to manage in serverless environments and optimized for working with high-throughput static prompts, where repeatability is the priority.

GPT-4o dominates the public interface, but OpenAI maintains o3 for flexibility and architectural diversification.

The two models do not exclude each other: they coexist to serve different uses and infrastructures within the ChatGPT ecosystem.

Currently, GPT-4o is the preferred model for both free and ChatGPT Plus use, but OpenAI continues to keep o3 active in parallel and makes it available for direct user selection on app and web. This is not simply a technical legacy, but an intentional choice to decouple infrastructural needs from those of the user interface. While GPT-4o evolves to offer an experience increasingly close to real-time human assistance, o3 remains a solid alternative for less dynamic but more controllable orchestrations. The coexistence of the two models allows OpenAI to cover a wider range of needs and use cases, while maintaining strategic flexibility in the evolution of its products.

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