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TV Screen Size Calculator

Convert a TV's diagonal inches and aspect ratio into the actual screen width, height, and diagonal in centimeters, plus the ideal viewing distance.

Input

in
Aspect ratio

Result

Screen size of a 55" 16:9 display

121.8×68.5cm

Width

121.8 cm

Height

68.5 cm

Diagonal

139.7 cm

Details & recommended viewing distance

Diagonal (inches)55" (139.7 cm)
Width121.8 cm
Height68.5 cm
Viewing distance (4K guide)approx. 102.7 cm and up
Viewing distance (Full HD guide)approx. 205.5 cm

How it works

  • A TV's size in inches refers to the length of the screen's diagonal. We convert it using 1 inch = 2.54 cm.
  • Width and height are derived from the diagonal length and the aspect ratio. For a ratio of w:h, width = diagonal × w/√(w²+h²) and height = diagonal × h/√(w²+h²).
  • You can choose from 16:9 (common for HDTV and 4K), 4:3 (older TVs), and 21:9 (ultrawide). For the same diagonal size, a different ratio gives different width and height.
  • When measuring the space for installation, remember that the bezel around the panel and the width of the stand add to the screen's own dimensions.
  • As a general guide, a comfortable viewing distance is about 1.5× the screen height for 4K and about 3× for Full HD. Adjust to suit your room size and personal preference.
  • These results are theoretical and may differ slightly from a product's actual dimensions. Always check the manufacturer's specifications before buying.