Star Magnitude Calculator
Calculate absolute magnitude from apparent magnitude and distance using the distance modulus formula. Includes luminosity ratio and parallax.
Inputs
pc
Results
Absolute Magnitude (M)
1
Distance Modulus
0 mag
Luminosity (vs Sun)
34.04 L☉
Distance32.62 ly
Distance2,062,650 AU
Flux Ratio (vs 10 pc)1
Brightness (vs Vega)0.3981
Parallax0.1 arcsec
How to Use This Calculator
- Enter the star's Apparent Magnitude (m) as observed from Earth — Sirius is −1.46, the Sun is −26.74, and the naked-eye limit is about +6.
- Enter the Distance (pc) to the star in parsecs — 1 pc = 3.26 light-years; Proxima Centauri is 1.3 pc.
- Read Absolute Magnitude (M) — the star's intrinsic brightness at a standard 10 pc distance.
- Use Luminosity (vs Sun) to compare output with familiar stars — the Sun is 1 L☉, Rigel is ~120,000 L☉.
- Check Parallax (arcsec): stars within ~100 pc have measurable parallax with Gaia-class precision.
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Formula
M = m - 5 × log₁₀(d/10)Related Calculators
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