Distance Modulus Calculator
Fill in the values and the answer updates as you type.
How the Distance Modulus Calculator works
Absolute magnitude is how bright a star would look from 10 parsecs away. The distance modulus m − M gives the distance: d = 10^((m − M + 5) ÷ 5) parsecs. One parsec is 3.26156 light-years. The method ignores dust between the stars, which dims the light and makes the star look farther than it is. Example: with Apparent magnitude 7.5 mag and Absolute magnitude 4.8 mag, the result is Distance (parsecs) = 34.67; Distance (light-years) = 113.09; Distance modulus (m − M) = 2.7.
Inputs and results
The Distance Modulus Calculator takes 2 inputs and gives 3 results.
What you enter
- Apparent magnitude (mag) — starts at 7.5.
- Absolute magnitude (mag) — starts at 4.8.
What you get
- Distance (parsecs)
- Distance (light-years)
- Distance modulus (m − M)
Example: Distance Modulus Calculator with the starting values
With apparent magnitude 7.5 mag and absolute magnitude 4.8 mag, the calculator returns:
| Distance (parsecs) | 34.67 |
|---|---|
| Distance (light-years) | 113.09 |
| Distance modulus (m − M) | 2.7 |
Change any value above and the results update straight away.
Distance Modulus Calculator FAQ
How do I use the Distance Modulus Calculator?
Enter apparent magnitude and absolute magnitude in the fields, then read distance (parsecs), distance (light-years) and distance modulus (m − m) in the result panel. The answer updates as you type, and you can press Calculate or Enter to refresh it. Use “Copy link” to share your exact numbers with someone else.
What does the Distance Modulus Calculator calculate?
Distance to a star from its apparent and absolute magnitude. It returns distance (parsecs), distance (light-years) and distance modulus (m − m) from the 2 values you provide.
What values does the Distance Modulus Calculator start with?
It opens with apparent magnitude 7.5 mag and absolute magnitude 4.8 mag so you can see a working result straight away. Replace them with your own numbers, or press Reset to return to these starting values.
Is the Distance Modulus Calculator free and private?
Yes. It is free, needs no account, and runs in your browser, so nothing you type is sent to or stored on our servers. See the Privacy Policy for details.
Can I rely on the Distance Modulus Calculator for important decisions?
Treat the result as a well-rounded estimate. Real situations often have details a general calculator cannot know, so confirm important decisions with a qualified professional. See the Disclaimer for more.