Diopters to focal length in centimeters
Type a value in D to get it in cm instantly.
50cm
That's about the same as reading glasses. That brings light to a focus about 500 mm away.
Convert the other way: cm to D
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 cm
Power and focal length are reciprocals: diopters = 1 ÷ focal length in meters, so focal length in mm = 1000 ÷ diopters.
Example: 2 D = 50 cm.
Every unit
Your lens in every unit
Tables
D to cm conversion table
| D | cm |
|---|---|
| 0.25 D | 400 cm |
| 0.5 D | 200 cm |
| 1 D | 100 cm |
| 1.5 D | 66.6667 cm |
| 2 D | 50 cm |
| 2.5 D | 40 cm |
| 3 D | 33.3333 cm |
| 4 D | 25 cm |
| 6 D | 16.6667 cm |
| 10 D | 10 cm |
| 20 D | 5 cm |
cm to D conversion table
| cm | D |
|---|---|
| 0.25 cm | 400 D |
| 0.5 cm | 200 D |
| 1 cm | 100 D |
| 1.5 cm | 66.6667 D |
| 2 cm | 50 D |
| 2.5 cm | 40 D |
| 3 cm | 33.3333 D |
| 4 cm | 25 D |
| 6 cm | 16.6667 D |
| 10 cm | 10 D |
| 20 cm | 5 D |
Quick answers
Quick answers
- How many cm is 1 D?
- 1 D is 100 cm.
- How many cm is 10 D?
- 10 D is 10 cm.
- How many cm is 2 D?
- 2 D is 50 cm.
The units
About these units
Diopters (D)
One divided by the focal length in meters. Diopters simply add.
Focal length in centimeters (cm)
The handy scale for magnifiers and close-up lenses.
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