Practical measurement guide
How to Measure Screen Size
Measure screen diagonal size correctly and understand why width and height are different.
How to Measure Screen Size gives a direct measurement method, verified examples, common mistakes, and links to the right calculator.
in
Decimals and fractions work, for example 1.5, 1/2, or 1 1/2.
cm
Try a value
Fractions
10 in = 25.4 cm
10 in × 2.54 = 25.4 cm
Decimal inches10 in
Feet + inches0 ft 10 in
Nearest 1/16 inch10"
Short method
Start with the unit shown on the measuring tool, convert with the exact factor where one exists, and round only after the calculation.
Worked example
For example, 10 inches × 2.54 = 25.4 cm. If a ruler fraction is involved, convert the fraction to decimal inches first.
Common mistakes
- Rounding before converting.
- Mixing diagonal screen size with width.
- Treating estimated measurements as exact specifications.
Related measurement tools
Frequently asked questions
Should I convert before rounding?
Yes. Convert first, then round the final displayed value for the task.
Can I use estimates for exact specifications?
No. Estimates are useful for rough planning, but exact specifications need a measured value.
Which tool should I use next?
Use the converter or chart linked on the page that matches your source and target units.