Diopters to focal length in meters
Type a value in D to get it in m instantly.
0.5m
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 m
Power and focal length are reciprocals: diopters = 1 ÷ focal length in meters, so focal length in mm = 1000 ÷ diopters.
Example: 2 D = 0.5 m.
Every unit
Your lens in every unit
Tables
D to m conversion table
| D | m |
|---|---|
| 0.25 D | 4 m |
| 0.5 D | 2 m |
| 1 D | 1 m |
| 1.5 D | 0.666667 m |
| 2 D | 0.5 m |
| 2.5 D | 0.4 m |
| 3 D | 0.333333 m |
| 4 D | 0.25 m |
| 6 D | 0.166667 m |
| 10 D | 0.1 m |
| 20 D | 0.05 m |
m to D conversion table
| m | D |
|---|---|
| 0.25 m | 4 D |
| 0.5 m | 2 D |
| 1 m | 1 D |
| 1.5 m | 0.666667 D |
| 2 m | 0.5 D |
| 2.5 m | 0.4 D |
| 3 m | 0.333333 D |
| 4 m | 0.25 D |
| 6 m | 0.166667 D |
| 10 m | 0.1 D |
| 20 m | 0.05 D |
Quick answers
Quick answers
- How many m is 1 D?
- 1 D is 1 m.
- How many m is 10 D?
- 10 D is 0.1 m.
- How many m is 2 D?
- 2 D is 0.5 m.
The units
About these units
Diopters (D)
One divided by the focal length in meters. Diopters simply add.
Focal length in meters (m)
Where parallel light comes to a focus.
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