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
| Topic | training |
|---|---|
| Last reviewed | 2026-06-24 |
Related terms
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:
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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.