HesapHanem

Screen Dimensions Calculator

Find a screen’s width and height.

How it is calculated

A screen is a rectangle, so its diagonal, width and height form a right triangle. With the ratio W:H, the diagonal corresponds to k = √(W² + H²) ratio units. Then width = diagonal × W / k and height = diagonal × H / k. The diagonal is read in inches and both results are given in inches, rounded to two decimals. Diagonal and both ratio numbers must be above zero. Any ratio works (16:9, 21:9, 4:3, 16:10), because only the proportion matters, not the absolute numbers. The result is the visible panel size, not the outer frame.

Worked example

A 27-inch monitor with a 16:9 ratio. First k = √(16² + 9²) = √337 ≈ 18.36. Width = 27 × 16 / 18.36 ≈ 23.53 in. Height = 27 × 9 / 18.36 ≈ 13.24 in. Check: 23.53² + 13.24² ≈ 729, which is 27². In centimetres that is about 59.8 cm wide and 33.6 cm tall.

Try this example →

Common mistakes

  • Assuming a 27-inch screen is 27 inches wide; the diagonal is always the longest side.
  • Entering the ratio as a decimal and a whole number inconsistently (1.78 and 1 is fine, but 16 and 1.78 is not).
  • Swapping the ratio numbers for a portrait screen: for a rotated display swap width and height or enter 9:16.
  • Comparing screens of different ratios by diagonal alone; a 21:9 ultrawide has less height than a 16:9 screen of the same diagonal.
  • Forgetting that bezels and stands are not included in the panel size.

About this calculator

This calculator uses the Pythagorean theorem together with an aspect ratio (like 16:9 or 21:9) to split a screen's diagonal measurement into its actual width and height — the diagonal number alone doesn't tell you how wide or tall a screen physically is.

It's used when shopping for a TV or monitor to check whether it will physically fit a piece of furniture or wall space, by home theater and cinema planners figuring out projector throw distances, and by developers or designers reasoning about display dimensions.

Was this helpful?

You can pick up to 3 reactions.

Comments (1)

  • Editorial team

    The width and height are the visible panel in inches, without bezel or stand, so measure the desk space with a little margin. You can enter any ratio, such as 21 and 9, and the same diagonal gives a much shorter, wider screen than 16 and 9, which is worth comparing before buying an ultrawide. Multiply by 2.54 for centimetres. Which ratio do you plan to use?

Popular calculators

Loan Calculator

Monthly payment, total interest and full amortization schedule.

Percentage Calculator

Percent change, percent of, and ratio calculations.

Discount Calculator

Calculate final price, savings, and discount amount.

BMI Calculator

Body mass index from height and weight (metric or imperial).

Age Calculator

Compute your exact age in years, months and days from a birth date.

Compound Interest Calculator

Calculate the final amount and interest earned with compounding.

All Calculators