Apparent magnitude to times fainter
Type a value in mag to get it in × fainter instantly.
251.2× fainter
That's 41× as bright as Polaris, while the naked-eye limit is 1.58× fainter. That is bright enough to see with the naked eye from a dark site.
Convert the other way: × fainter to mag
What it means
How bright is that?
These are apparent magnitudes: how bright something looks from Earth, not how much light it truly gives out.
The math
How to convert mag to × fainter
Magnitude is logarithmic and inverted: m = −2.5 × log₁₀(brightness ratio), and back again ratio = 10^(−m ÷ 2.5). Five magnitudes is exactly a hundredfold.
Example: 6 mag = 251.189 × fainter.
Every unit
Your brightness in every unit
Tables
mag to × fainter conversion table
| mag | × fainter |
|---|---|
| -26 mag | 3.981×10⁻¹¹ × fainter |
| -12 mag | 1.585×10⁻⁵ × fainter |
| -4 mag | 0.0251189 × fainter |
| -1 mag | 0.398107 × fainter |
| 0 mag | 1 × fainter |
| 1 mag | 2.51189 × fainter |
| 3 mag | 15.8489 × fainter |
| 6 mag | 251.189 × fainter |
| 10 mag | 10,000 × fainter |
| 15 mag | 1,000,000 × fainter |
| 20 mag | 100,000,000 × fainter |
| 25 mag | 1×10¹⁰ × fainter |
× fainter to mag conversion table
| × fainter | mag |
|---|---|
| 3.98×10⁻¹¹ × fainter | -26.0003 mag |
| 1.58×10⁻⁵ × fainter | -12.0034 mag |
| 0.0251 × fainter | -4.00082 mag |
| 0.398 × fainter | -1.00029 mag |
| 1 × fainter | 0 mag |
| 2.51 × fainter | 0.999184 mag |
| 15.8 × fainter | 2.99664 mag |
| 251 × fainter | 5.99918 mag |
| 10,000 × fainter | 10 mag |
| 1,000,000 × fainter | 15 mag |
| 100,000,000 × fainter | 20 mag |
| 1×10¹⁰ × fainter | 25 mag |
Quick answers
Quick answers
- How many × fainter is 1 mag?
- 1 mag is 2.51189 × fainter.
- How many × fainter is 10 mag?
- 10 mag is 10,000 × fainter.
- How many × fainter is 6 mag?
- 6 mag is 251.189 × fainter.
The units
About these units
Apparent magnitude (mag)
The astronomer’s brightness scale, running backwards from bright to faint.
Times fainter (× fainter)
How many times fainter than a magnitude 0 star such as Vega.
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