Screen Size Inches to CM Converter for TVs and Monitors
Screen Size Inches to CM Converter. Type a value in Inches or Centimeters to convert your screen size inches to cm or back. The px to mm converter tool handles the conversion entirely client-side, so nothing you enter is ever transmitted.
Interactive Tool
Common Screen Sizes
| Inches | Centimeters |
|---|---|
| 21.5" | 54.6 cm |
| 24" | 61.0 cm |
| 27" | 68.6 cm |
| 32" | 81.3 cm |
| 42" | 106.7 cm |
| 55" | 139.7 cm |
| 65" | 165.1 cm |
| 75" | 190.5 cm |
The Screen Size Unit Converter converts a display's diagonal measurement between inches and centimeters in either direction, making screen size inches to cm a one-step job, which matters everywhere monitors and TVs are marketed in centimeters but spec sheets still use inches. Type a value into either the Inches field or the Centimeters field and the other one updates as you type — no separate convert button, no picking a direction first. A reference table of common screen sizes sits below both fields if you just want to look one up rather than type it in.
Use this screen size inches to cm converter to turn the diagonal on a TV, monitor or television spec sheet into metric units, then work out the real width and height of the display. A screen size label gives you only one number, so a 65-inch panel tells you little about how much shelf or desk space it needs. Converting inches to centimeters is a single multiplication, and once you add the aspect ratio you can measure the whole screen before you buy, whatever the TV size.
Screen Size Inches to CM Converter Formula
Every screen size is quoted as a diagonal: the straight line from the bottom left corner to the top right corner of the visible image. One inch is exactly 2.54 cm, so the formula is: Run the retina display distance calculator online to double-check a result before you rely on it for something important.
$$\text{cm} = \text{inches} \times 2.54$$
To go the other way, divide the measurement in cm by 2.54. A 34-inch screen works out at 34 × 2.54 = 86.36 cm, and 86.36 ÷ 2.54 returns 34 again. That figure is the screen size in cm, the same length a tape shows from corner to corner, and the inch size printed on the box is simply its rounded version. That single number says nothing about each side or the proportion of the panel, which is why the next sections add the aspect ratio.
Measuring a Diagonal Screen Size by Hand
Pull a soft measuring tape from the bottom left corner of the lit area to the top right corner, ignoring the bezel and the stand. Skip a metal tape measure, which can scratch the glass, and hold the tape flat at the same angle as the panel so it does not sag. Say you read 164 cm on a television hanging on the wall: 164 ÷ 2.54 = 64.57, which rounds to a 65-inch TV, because makers round the marketing number to the nearest whole inch.
TV Dimensions in Centimeters for Common Sizes
This table lists the TV dimensions of the widescreen sizes sold most often, calculated with the method in the next section. Use it as a lookup instead of running the converter for every model. Catalogues round to the nearest centimeter, so expect a few millimeters of difference between brands, and a curved or flat screen type does not change the listed figures. Run the monitor field of view calculator tool to double-check a result before you rely on it for something important.
| Inch size | Diagonal (cm) | Width (cm) | Height (cm) |
|---|---|---|---|
| 32 inches | 81.3 cm | 70.8 cm | 39.8 cm |
| 43 inches | 109.2 cm | 95.2 cm | 53.5 cm |
| 50 inches | 127.0 cm | 110.7 cm | 62.3 cm |
| 55 inches | 139.7 cm | 121.8 cm | 68.5 cm |
| 65 inches | 165.1 cm | 143.9 cm | 80.9 cm |
| 75 inches | 190.5 cm | 166.0 cm | 93.4 cm |
| 85 inches | 215.9 cm | 188.2 cm | 105.8 cm |
Small, Medium and Large TV Sizes
Small TV sizes up to 32 inches suit a bedroom or kitchen, where the room is tight. Medium sets of 40 to 55 inches fit most a living room, usually facing a sofa about two meters away. From 65 inches upward you are in home theater territory, so check the TV against your cabinet and the doorway before you order.
Is a 55 Inch TV Too Big?
At 121.8 cm wide and 68.5 cm tall, a 55-inch TV fits a standard 140 cm console, so check your own furniture in cm and compare. Whether it is too big then depends on how far back you sit: a Full HD panel shows its pixel structure sooner than an Ultra HD one, so a sharper picture lets you sit closer and improves the viewing experience in a small room.
Fitting a 31.5-Inch Monitor into a Shelf Nook: Inches to Centimeters in Practice
I'm deciding whether a 31.5-inch monitor will sit on a bookshelf nook that I measure at 72.0 cm wide and 46.5 cm tall. The shop lists only inches, so I run the conversion first: 31.5 × 2.54 gives a diagonal of 80.01 cm. A flat 16:9 panel is 0.872 times that wide and 0.490 times that tall, so I enter 31.5 and 16:9 and read back a width of 69.73 cm and a height of 39.23 cm.
The number I watch is the width, because the nook is the tight dimension. The viewable area is not the whole product, though. Spec sheets quote the outer width, and I assume a 1.0 cm bezel on each side, which makes the real footprint 69.73 + 2.0 = 71.73 cm. That leaves just 0.27 cm of slack against 72.0 cm, which is tight but workable, and the 39.23 cm height clears the 46.5 cm opening with room for the stand.
| Diagonal | Viewable width | Outer width (with bezel) | Fits 72.0 cm? |
|---|---|---|---|
| 31.5 inches | 69.73 cm | 71.73 cm | Yes, by 0.27 cm |
| 32 inches | 70.84 cm | 72.84 cm | No, over by 0.84 cm |
The sensitivity rerun is what settles it. Changing the diagonal by half an inch to 32 inches adds 1.11 cm of width and breaks the fit. Solving backwards, the largest 16:9 diagonal whose outer width stays within 72.0 cm is (72.0 − 2.0) ÷ (0.872 × 2.54) = 31.6 inches, so 31.5 is the biggest size on the shelf. I check it a second way by measuring the old monitor's diagonal with a tape: 68.6 cm, which converts to 27 inches and a width of 59.77 cm, matching its spec sheet.
The edge case is the bezel guess. A thick-bezel model or a stand that flares wider than the panel would push the footprint past 72.0 cm even at 31.5 inches, and the converter cannot see that, so I treat its answer as a viewable-size check only and confirm the outer width on the data sheet before I order.
Screen Dimensions: Width and Height from the Diagonal and Aspect Ratio
The aspect ratio is the proportion between the width and the height of the rectangle, written as two numbers such as 16:9. It does not say how large the screen is, only its shape; together with the diagonal it fixes both sides. The Pythagorean theorem links them, since the diagonal is the hypotenuse of a right triangle:
$$d^{2} = w^{2} + h^{2}$$
With \(AR = w / h\), taking the square root gives the height, and the width follows from it:
$$h = \frac{d}{\sqrt{AR^{2} + 1}} \qquad w = AR \times h$$
Trigonometry gives the same answer: the angle between the diagonal and the width is \(\arctan(h / w)\), about 29.36° for a wide TV. Take the 34-inch panel from above at 21:9, so \(AR = 21/9 = 2.333\). Its 86.36 cm span gives \(h = 86.36 / \sqrt{2.333^{2} + 1} = 34.02\) cm and \(w = 2.333 \times 34.02 = 79.38\) cm. A rectangle's area is width times height, so the screen area is 79.38 × 34.02 ≈ 2,700 cm². Other shapes follow the same pattern, such as 4:3 on older desktop screens, 16:10 on some notebook panels and 2.39:1 on cinema screens. The pixel count of a panel never changes its physical size, so resolution is irrelevant here, and the screen width and screen height come from the ratio alone.
How Big Is a 16:9 Screen?
For 16:9 the constants are fixed: h = 0.490 × d and w = 0.872 × d. Any screen size calculator or TV size calculator applies these two numbers, which is why a 65-inch TV is 143.9 cm wide whatever the brand. The thickness of the cabinet and stand is a separate spec you read from the data sheet.
Phone, Laptop and Tablet Screens
The same screen size dimensions logic works on a phone screen. A 6.1-inch iPhone at 19.5:9 measures about 14.07 cm on its long side and 6.49 cm on its short side, and any smartphone, laptop or tablet can be checked the same way. Makers usually quote only the inches, so enter the phone's inches and ratio into the converter to get its sides in cm, and compare an iPhone or Android handset by shape first and by size second.
Monitor Size on a Curved Screen
A curved screen is measured along the surface, so a tape pressed against the glass reads the same size as on a flat panel. The curvature rating, such as 1500R, is the radius of the circle in millimeters, here R = 150 cm. The face of the 34-inch panel is an arc about 79.38 cm long, and the straight chord and the space it occupies follow from:
$$\text{chord} = 2R \sin\left(\frac{L}{2R}\right) \qquad \text{depth} = R\left(1 - \cos\frac{L}{2R}\right)$$
That gives a chord of 78.45 cm and a depth of 5.22 cm, so the curved panel is slightly narrower than a flat one but sticks out further toward you. The inch figure itself converts to cm exactly as on a flat panel; the chord and the space behind are extra footprint checks the converter does not perform. Allow that extra room when you measure a desk.
TV Size and Viewing Distance
The cm result from the converter is the input for every distance rule below, so once you know the length in cm, choose where to put your TV and where to sit. Too close and you pick up eye strain; too far and the picture loses its impact, which hurts the viewing experience whatever the room. Rules of thumb scale with the corner-to-corner length, and they apply equally to a projector screen, where the projector image replaces the TV size and the throw distance replaces the sofa.
Viewing Distance for 4K and Full HD
For an HD set, a common rule is 4.2 cm of viewing distance per inch of screen size. A 4K panel has finer resolution, so you can multiply the screen size in cm by 1.2 instead: a 65-inch TV at 165.1 cm needs 165.1 × 1.2 ≈ 198 cm. Treat it as a starting distance for your room, not a hard limit, and measure the real space before you buy.
Mount Height and Eye Level
Fix the wall mount so the middle of the screen sits at eye level or slightly below, which is roughly one meter off the floor for a seated viewer. Use the table: a 65-inch TV is 80.9 cm tall, so centering it at 100 cm puts its top edge near 140 cm. Looking up at the TV for hours is a quick route to eye strain, so tilt it down if you must fit it higher.
Frequently Asked Questions
- How do I convert a screen size in inches to cm?
- Multiply the diagonal in inches by 2.54, because one inch is exactly 2.54 centimeters. A 55-inch screen has a diagonal of 139.7 cm, and dividing a centimeter reading by 2.54 takes you back to inches.
- How do I find a screen's width and height from its diagonal?
- You need the aspect ratio too. The diagonal is the hypotenuse of a right triangle, so height = diagonal ÷ √(ratio² + 1) and width = ratio × height. For 16:9 that works out to about 0.872 × diagonal for the width and 0.490 × diagonal for the height.
- How do I measure the screen size of my TV or monitor?
- Use a soft measuring tape from the bottom left corner of the visible picture to the top right corner, ignoring the bezel and stand. Enter that length with the right unit and the converter returns the inch size, width and height.
- Does a curved screen change the diagonal?
- No. You measure a curved screen along its surface and the diagonal is read the same way as on a flat panel. The curvature rating changes the straight-line base width and the depth the screen takes up, which the converter shows when you pick Curved.
- Which aspect ratio should I choose?
- Pick 16:9 for most modern TVs and monitors, 16:10 for many laptops, 21:9 or 32:9 for ultrawide monitors and 4:3 for older displays. If your screen has an unusual shape, choose Custom and type in the two ratio numbers.
- Is the screen size the same as the size of the whole TV?
- No. The quoted inch size is only the visible screen diagonal. The bezel and stand add to the outer width and height, so check the outer dimensions on the spec sheet before you fit a TV into a cabinet or onto a wall.
- How far should I sit from my TV?
- A common rule for a 4K TV is to multiply the diagonal in cm by 1.2, so a 55-inch set at 139.7 cm suits a distance of about 168 cm. For a Full HD set, many guides suggest around 4.2 cm per inch of diagonal.