Diopters to magnifier power
Type a value in D to get it in × instantly.
0.5×
That's about the same as reading glasses. That brings light to a focus about 500 mm away.
What it means
How strong is that lens?
Prescriptions carry a cylinder and an axis as well, for astigmatism. This page converts the sphere, which is the main number.
The math
How to convert D to ×
Power and focal length are reciprocals: diopters = 1 ÷ focal length in meters, so focal length in mm = 1000 ÷ diopters.
Example: 2 D = 0.5 ×.
Every unit
Your lens in every unit
Tables
D to × conversion table
| D | × |
|---|---|
| 0.25 D | 0.0625 × |
| 0.5 D | 0.125 × |
| 1 D | 0.25 × |
| 1.5 D | 0.375 × |
| 2 D | 0.5 × |
| 2.5 D | 0.625 × |
| 3 D | 0.75 × |
| 4 D | 1 × |
| 6 D | 1.5 × |
| 10 D | 2.5 × |
| 20 D | 5 × |
× to D conversion table
| × | D |
|---|---|
| 0.25 × | 1 D |
| 0.5 × | 2 D |
| 1 × | 4 D |
| 1.5 × | 6 D |
| 2 × | 8 D |
| 2.5 × | 10 D |
| 3 × | 12 D |
| 4 × | 16 D |
| 6 × | 24 D |
| 10 × | 40 D |
| 20 × | 80 D |
Quick answers
Quick answers
- How many × is 1 D?
- 1 D is 0.25 ×.
- How many × is 10 D?
- 10 D is 2.5 ×.
- How many × is 2 D?
- 2 D is 0.5 ×.
The units
About these units
Diopters (D)
One divided by the focal length in meters. Diopters simply add.
Magnifier power (×)
Magnification at the standard 250 mm near point.
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