Fine-tuning now available for GPT-4o

Fine-tune custom versions of GPT‑4o to increase performance and accuracy for your applications.

Update on May 8, 2026: OpenAI is winding down the fine-tuning platform. The platform is no longer accessible to new users but existing users of the fine-tuning platform will be able to create training jobs for the coming months. All fine-tuned models will remain available for inference until their base models are deprecated⁠(opens in a new window). The full timeline is here⁠(opens in a new window).

Today, we’re launching fine-tuning for GPT‑4o⁠, one of the most requested features from developers. We are also offering 1M training tokens per day for free for every organization through September 23.

Developers can now fine-tune GPT‑4o with custom datasets to get higher performance at a lower cost for their specific use cases. Fine-tuning enables the model to customize structure and tone of responses, or to follow complex domain-specific instructions. Developers can already produce strong results for their applications with as little as a few dozen examples in their training data set.

From coding to creative writing, fine-tuning can have a large impact on model performance across a variety of domains. This is just the start—we’ll continue to invest in expanding our model customization⁠ options for developers.

Getting started

GPT‑4o fine-tuning is available today to all developers on all paid usage tiers⁠(opens in a new window).

To get started, visit the fine-tuning dashboard⁠(opens in a new window), click create, and select gpt-4o-2024-08-06 from the base model drop-down. GPT‑4o fine-tuning training costs $25 per million tokens, and inference is $3.75 per million input tokens and $15 per million output tokens.

GPT‑4o mini fine-tuning is also available to all developers on all paid usage tiers. Visit the fine-tuning dashboard and select gpt-4o-mini-2024-07-18 from the base model drop-down. For GPT‑4o mini, we’re offering 2M training tokens per day for free through September 23.