Convert Inches to Centimeters for Screen Sizes
This converter instantly switches between inches and centimeters for screen sizes — monitors, TVs, tablets, smartphones, and laptops. Screen size is always measured diagonally, corner to corner, across the display panel. The core formulas are: inches → cm: multiply by 2.54 (1 in = 2.54 cm exactly, per NIST definition); cm → inches: divide by 2.54. Use this tool when comparing products listed in different unit systems, verifying mounting or desk clearance specs, or shopping internationally where screen sizes may be advertised in cm (common in Europe and Latin America) rather than inches (standard in the US, UK, and Canada).
When to use this calculator
- Comparing a US-listed 65-inch TV with a European listing showing 165 cm to confirm they're the same panel before purchasing.
- Calculating whether a 27-inch (68.58 cm) monitor fits within a 70 cm desk hutch opening without measuring the physical unit.
- Converting a smartphone screen from 6.7 inches to 17.02 cm to match the spec sheet format required by a carrier or retailer.
- Verifying that a 15.6-inch laptop display (39.62 cm) meets the minimum screen size requirement for a graphics-intensive software license.
- Determining the physical diagonal of a 32-inch (81.28 cm) TV to choose the correct VESA wall-mount bracket reach and arm length.
Calculation Example
- Typical Value
- Result
How it works
3 min readHow It's Calculated
The inch-to-centimeter relationship is exact — not an approximation — established by international agreement and codified by NIST:
inches → centimeters: cm = inches × 2.54
centimeters → inches: in = cm ÷ 2.54
Example 1: 27 in × 2.54 = 68.58 cm
Example 2: 81.28 cm ÷ 2.54 = 32.00 inScreen size always refers to the diagonal measurement of the active display area, not the width or height, and does not include the bezel (frame).
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Reference Table
| Screen Size (in) | Screen Size (cm) | Common Device |
|---|---|---|
| 4.7 | 11.94 | iPhone SE / small smartphone |
| 6.1 | 15.49 | iPhone 15 / mid-size smartphone |
| 6.7 | 17.02 | Large smartphone / phablet |
| 10.9 | 27.69 | iPad Air (10th gen) |
| 11.0 | 27.94 | iPad Pro 11-inch |
| 13.3 | 33.78 | MacBook Air 13 / common laptop |
| 15.6 | 39.62 | Standard laptop |
| 21.5 | 54.61 | Entry-level desktop monitor |
| 24.0 | 60.96 | Popular office monitor |
| 27.0 | 68.58 | Standard desktop monitor |
| 32.0 | 81.28 | Large monitor / small TV |
| 43.0 | 109.22 | Mid-size TV |
| 55.0 | 139.70 | Large TV |
| 65.0 | 165.10 | XL TV |
| 75.0 | 190.50 | Home theater TV |
| 85.0 | 215.90 | Ultra-large TV |
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Typical Cases
Case 1 — Monitor desk fit check:
You want a 27-inch monitor but your shelf opening is 65 cm wide. The diagonal is 68.58 cm, but that's corner-to-corner — the width of a typical 16:9 27-inch panel is about 59.8 cm (diagonal × cos(arctan(9/16)) ≈ diagonal × 0.872). So 59.8 cm < 65 cm: it fits width-wise, with ~5 cm to spare.
Case 2 — International TV purchase:
A European retailer lists a TV as "164 cm." Dividing: 164 ÷ 2.54 = 64.57 inches — effectively a 65-inch class TV (manufacturers round to the nearest inch). Knowing this prevents paying a premium thinking it's a different size tier.
Case 3 — Laptop for software compliance:
A CAD software vendor requires a minimum display of 38 cm diagonal. A 15-inch laptop = 15 × 2.54 = 38.10 cm — just barely meets the threshold. A 14-inch laptop = 35.56 cm — does not qualify.
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Common Errors
1. Measuring bezel-to-bezel instead of screen-to-screen. Manufacturers measure only the active display area diagonally. The physical chassis is always larger. A "27-inch" monitor's outer frame may span 63–65 cm wide.
2. Confusing diagonal with width or height. "55 inches" is the diagonal of the screen, not its width. For a 16:9 TV, width ≈ diagonal × 0.872 and height ≈ diagonal × 0.490. A 55-inch TV is roughly 121.3 cm wide and 68.2 cm tall.
3. Using an approximate factor (2.53 or 2.55). The exact factor is 2.54 with no rounding. Over a 75-inch screen, using 2.55 introduces a 0.75 cm error — enough to matter for tight installations.
4. Assuming advertised size equals exact size. A "55-inch" TV may actually measure 54.5 or 54.6 inches diagonally; manufacturers label by nominal class, not exact measurement. Always check the spec sheet for the precise diagonal figure.
5. Forgetting that phone screens exclude the notch/camera cutout area. Manufacturers report the full rectangular diagonal even when part of the top is physically blocked by a camera island or notch, so the usable display area is slightly smaller than the advertised figure.
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Related Calculators
Since no internal related slugs were specified for this calculator, explore other unit conversion and measurement tools on Hacé Cuentas to find area, resolution (PPI), and aspect ratio calculators that complement screen size conversions.
Frequently asked questions
Why is 1 inch exactly 2.54 centimeters and not an approximation?
The 1959 International Yard and Pound Agreement, adopted by the US, UK, Canada, Australia, and others, defined the international inch as exactly 2.54 cm. NIST confirms this as an exact, invariant definition — not a measured or rounded value. There is zero rounding error in this conversion.
Is screen size always measured diagonally?
Yes. The consumer electronics industry universally measures display size as the diagonal of the active screen area, following convention established in the early CRT television era. Width and height are not used for the advertised size. For a 16:9 aspect ratio, width ≈ diagonal × 0.8716 and height ≈ diagonal × 0.4903.
How do I convert a 65-inch TV size to centimeters?
Multiply by 2.54: 65 × 2.54 = 165.10 cm. This is the diagonal of the active screen. The physical width of a 16:9 65-inch TV is approximately 65 × 0.8716 ≈ 56.65 inches ≈ 143.9 cm, and height is about 65 × 0.4903 ≈ 31.87 inches ≈ 80.9 cm — useful for checking if it fits on a TV stand or wall space.
What is the screen size in inches for a 40 cm display?
Divide by 2.54: 40 ÷ 2.54 = 15.75 inches. This is closest to the 15.6-inch laptop class (39.62 cm), meaning a true 40 cm panel is slightly larger than a standard 15.6-inch laptop — roughly comparable to a 16-inch laptop class (40.64 cm).
Does the bezel affect the advertised screen size in inches or cm?
No. The advertised screen size refers only to the active display area (the lit panel), measured diagonally corner to corner. The bezel adds several centimeters to the physical device footprint but is never included in the screen size specification. A 27-inch (68.58 cm) monitor's full chassis width is typically 63–65 cm.
Why do European retailers list TV sizes in cm while US retailers use inches?
The metric system is the official measurement standard throughout the European Union (mandated by EU Directive 80/181/EEC), so consumer products are labeled in centimeters. The US predominantly uses the US customary system, where inches are conventional for screen sizes. Both values describe the same diagonal; only the unit differs. A '139 cm TV' and a '55-inch TV' are the same size class (139 ÷ 2.54 = 54.72 in, rounded to 55-inch class).
What is PPI (pixels per inch) and how does screen size in inches affect it?
PPI = √(horizontal_pixels² + vertical_pixels²) ÷ diagonal_inches. For a 27-inch 1920×1080 monitor: √(1920²+1080²) = 2202.9 pixels ÷ 27 = 81.6 PPI. The same resolution on a 24-inch screen = 2202.9 ÷ 24 = 91.8 PPI — sharper because the same pixels are packed into a smaller area. Converting diagonal to inches first is the required step for this formula.
Are there any screens where the nominal size doesn't match the actual diagonal?
Yes — manufacturers use 'size class' labeling, where a '55-inch TV' may actually measure 54.5 to 54.9 inches diagonally. The FTC does not require exact match between the label and measured diagonal as long as the specification sheet discloses the actual viewable size. Always check the product spec sheet's 'viewable area' field for precise measurements when installation clearance is critical.