Screen Size Calculator
Find the actual width, height, and area of any screen from its diagonal and aspect ratio.
This tool is for informational and educational purposes only. It is not a substitute for professional financial, medical, legal, or engineering advice. See Terms of Service.
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Request a ToolHow to Use the Screen Size Calculator
- Choose an aspect ratio preset or enter custom values in the ratio fields. Most modern TVs and monitors are 16:9. Ultrawide monitors are typically 21:9 or 32:9. Older displays may be 4:3 or 5:4.
- Enter the diagonal size in inches. This is the measurement advertised on the box and listed on specifications pages. It is measured corner to corner across the screen.
- Read the results. The calculator shows the actual width, height, and total screen area in square inches.
Tip: when comparing two TVs labeled different sizes (e.g. 55" vs 65"), the screen area scales with the square of the ratio. A 65" screen has about 40% more area than a 55" screen despite being only 18% larger in diagonal.
About Screen Size Measurements
Screen size is always measured diagonally from corner to corner of the active display area, not including the bezel. A 55-inch 16:9 TV has a width of about 47.9 inches and a height of about 26.9 inches. The bezel adds a few more inches to the physical dimensions of the set, which matters for mounting and cabinet sizing.
For seating distance, a common rule of thumb is to sit at a distance equal to 1.5 to 2.5 times the screen's diagonal. For a 65" screen, that suggests 8 to 13 feet. At that distance, a 4K TV at 65" will not appear noticeably sharper than 1080p to most viewers — you need to sit closer or use a larger screen for 4K to make a visible difference.
Frequently Asked Questions
How wide is a 65-inch TV?
A 65-inch 16:9 TV screen is approximately 56.7 inches wide and 31.9 inches tall. Add the bezel width (typically 0.5 to 1 inch per side on modern TVs) for the total physical width. The exact dimensions vary slightly by manufacturer.
What is the actual screen size of a 27-inch monitor?
A 27-inch 16:9 monitor is approximately 23.5 inches wide and 13.2 inches tall. A 27-inch 16:10 monitor (common on Mac displays) is about 22.9 inches wide and 14.3 inches tall. The 16:10 version has a taller screen despite the same diagonal.
How do I compare screen sizes when buying a TV?
Use the screen area to compare. A 75-inch TV has roughly 73% more screen area than a 55-inch TV. Diagonal measurements can be misleading because area grows with the square of the diagonal. Calculate both widths and heights, then consider your room width, viewing distance, and wall space before deciding.
Does a 4:3 or 16:9 TV look bigger for the same diagonal?
A 4:3 TV at the same diagonal is taller and has more screen area than a 16:9 TV of the same diagonal. A 32-inch 4:3 TV has about 491 square inches of screen versus 442 for a 32-inch 16:9 TV. However, 16:9 is wider, which better fills your field of view when watching widescreen content without black bars.