ModelRefs / Fine-Tuning — AI Glossary

Fine-Tuning — AI Glossary

Additional training of a pretrained model on task- or domain-specific data to specialize its behavior.

Overview

Full fine-tuning updates all model weights and is expensive. Parameter-efficient methods like LoRA and QLoRA update a small adapter and are the modern default for most production use cases. Fine-tuning typically requires 100K–1M curated examples to meaningfully improve over prompting.

Reference details

Topictraining
Last reviewed2026-06-24

Example: The question that decides it

A model that will not hold your house JSON format across 50 turns needs fine-tuning: the behaviour is the problem. A model that does not know your Q3 pricing needs retrieval: the knowledge is the problem. Fine-tuning teaches form and style reliably and is a poor and expensive way to install facts, because facts change and weights do not.

Commonly confused with

Fine-tuning adjusts behaviour far more reliably than it adds knowledge. Facts trained into weights cannot be cited, updated or revoked per tenant, and they go stale silently — which is why retrieval, not fine-tuning, is the normal answer to “the model does not know X”.

When to use it

Reach for it when:

  • You need a consistent format, tone or structure that prompting keeps missing
  • The task is narrow and you have curated examples of it done correctly
  • Prompt length has become a recurring cost you want to compile away

Reach for something else when:

  • The knowledge changes — you will be retraining forever
  • You have a few hundred examples; that usually teaches noise
  • You have not yet exhausted prompting and retrieval, which are cheaper to reverse

Referenced by

This term is used by the following ModelRefs references:

Continue your research

Use these connected ModelRefs sections to compare alternatives, inspect implementation paths, and review the evidence and governance boundaries relevant to Fine-Tuning — AI Glossary.

Frequently asked questions

What is Fine-Tuning?

Additional training of a pretrained model on task- or domain-specific data to specialize its behavior.

What concepts are related to Fine-Tuning?

Closely related concepts include lora, rlhf, sft, synthetic data.