Enter the radius and temperature of a start into the calculator to determine its luminosity.

Luminosity Formula

The following formula is used to calculate the luminosity of a star.

L = 4 * pi * R2 * SB * T4 
  • Where L is the luminosity
  • R is the radius of the star (m)
  • SB is the Stefan-Boltzmann constant (5.670*10-8 W*m-2 * K-4 )
  • T is the temperature (K)

Luminosity Definition

Luminosity is defined as the radiant energy or power given off by a star.

Luminosity Example

How to calculate luminosity?

  1. First, determine the radius.

    Calculate the radius of the start.

  2. Next, determine the temperature.

    Calculate the surface temperature of the star.

  3. Finally, calculate the luminosity.

    Calculate the luminosity of the star using the equation above.


What is luminosity?

Luminosity is a measure of the radiant power given off by an object. This object is most often a start or large celestial body.

What is radiant power?

Radiant power is the total energy emitted by light-producing object through radiant flux.