---
title: "Landauer limit · Library · Simulation Hypothesis"
url: https://simulation-hypothesis.com/library/landauer-limit
description: "The Landauer limit is the least energy it takes to erase one bit of information."
license: https://creativecommons.org/licenses/by/4.0/
credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)"
---

## Physics & computation

# Landauer limit

Definition

The Landauer limit is the least energy it takes to erase one bit of information. Rolf Landauer (1961) showed it’s at least kT ln 2, about 3 × 10^-21 joules at room temperature.

On this site

The Power tile multiplies the computing needed by this figure to get watts, then shows the result in solar luminosities. The most efficient hardware measured gives off about five billion times the limit per operation.

Role in the model

The Power tile multiplies the computing needed by the Landauer limit to get heat output, then shows it in Suns. Even with perfect hardware, a simulation this size has to give off at least this much heat somewhere. The most efficient hardware measured gives off about five billion times more per operation.

Related

[Lloyd’s bound](https://simulation-hypothesis.com/library/lloyd-bound)[FLOPS](https://simulation-hypothesis.com/library/flops)

In the trees

[Reversible computing · Technology](https://simulation-hypothesis.com/trees/technology?n=reversible)[The cost of forgetting · Becoming synthetic](https://simulation-hypothesis.com/trees/synthetic?n=landauer-1961)

## The people behind the terms

14 short pages, one per thinker, each with its matching dial. See also the [reading list](https://simulation-hypothesis.com/reading).

[Plato’s cave](https://simulation-hypothesis.com/thinkers/plato)[Zhuangzi’s butterfly](https://simulation-hypothesis.com/thinkers/zhuangzi)[Vasubandhu’s dream](https://simulation-hypothesis.com/thinkers/vasubandhu)[Shankara’s māyā](https://simulation-hypothesis.com/thinkers/shankara)[al-Ghazali’s doubt](https://simulation-hypothesis.com/thinkers/ghazali)[Ibn Arabi’s imagination](https://simulation-hypothesis.com/thinkers/ibn-arabi)[Calderón’s life is a dream](https://simulation-hypothesis.com/thinkers/calderon)[Descartes’ demon](https://simulation-hypothesis.com/thinkers/descartes)[Berkeley’s perceiver](https://simulation-hypothesis.com/thinkers/berkeley)[Borges’ circular ruins](https://simulation-hypothesis.com/thinkers/borges)[Nozick’s experience machine](https://simulation-hypothesis.com/thinkers/nozick)[Putnam’s brain in a vat](https://simulation-hypothesis.com/thinkers/putnam)[Bostrom’s trilemma](https://simulation-hypothesis.com/thinkers/bostrom)[Chalmers: virtual worlds are real](https://simulation-hypothesis.com/thinkers/chalmers)