ModelRefs / Top-P (Nucleus Sampling) — AI Glossary

Top-P (Nucleus Sampling) — AI Glossary

A decoding parameter that restricts sampling to the smallest set of tokens whose cumulative probability exceeds p. Typically used alongside temperature.

Overview

Top-P (e.g. 0.9) keeps generation diverse while avoiding low-probability tail tokens. Typically used alongside temperature. Setting top-p=1.0 disables nucleus sampling.

Reference details

Topicinference
Last reviewed2026-06-24

Commonly confused with

Top-p and top-k both restrict which tokens can be sampled, and differ in how the cut is decided: top-k always keeps a fixed number, top-p keeps as many as it takes to reach a probability mass, so it widens where the model is unsure and narrows where it is confident. Temperature is a separate control that reshapes the distribution before either cut. Changing more than one at a time makes the result uninterpretable.

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Frequently asked questions

What is Top-P (Nucleus Sampling)?

A decoding parameter that restricts sampling to the smallest set of tokens whose cumulative probability exceeds p.

What concepts are related to Top-P (Nucleus Sampling)?

Closely related concepts include temperature.