Convert inches to centimetres
Translate screen, wheel or pipe measurements into centimetres.
Calculator inputs
Results
Enter your values and press “Calculate” to see the result.
In short
- What it calculates
- Translate screen, wheel or pipe measurements into centimetres.
- Formula used
centimetres = inches × 2.54- Example
- A 15.6 inch screen:
Inches to centimetres converter
Screens, bicycles, pipes and many technical components are sized in inches even when the rest of the product is metric.
How it works
The inches are multiplied by 2.54. This factor has been exact by definition since 1959, so no rounding is involved.
Formula
centimetres = inches × 2.54
1 in = 2.54 cm exactly
1 cm = 0.393701 in
Worked example
A 15.6 inch screen:
15.6 × 2.54 = 39.62 cm diagonal
A 55" television measures 139.7 cm across the diagonal.
Explanation
Screen inches are deceptive
They are measured diagonally, so two screens of the same inch size can have very different areas depending on their aspect ratio. A 6.7-inch phone in a tall format has considerably less area than an old 6.7-inch tablet in 4:3. Comparing diagonals alone leads to surprises when the device arrives.
Where inches turn up day to day
Pipe and bicycle wheel diameters, screw sizes, letter-format paper, monitors, televisions, car wheels and tool gauges. In plumbing and mechanics both scales coexist, and using a metric spanner on an imperial bolt is the fastest way to round off a head.
The 2.54 rule
It is an exact factor by definition, not an approximation. Multiplying by 2.54 converts inches to centimetres without loss. Mentally, multiplying by 2.5 and adding one and a half per cent gets you very close.
Fractions rather than decimals
Inch measurements are usually expressed as fractions: a quarter, three eighths, a half, five eighths. Half an inch is 12.7 mm and a quarter is 6.35 mm. English-language catalogues rarely use decimals for these sizes.
Frequently asked questions
Is a screen’s inch measurement the diagonal?
Yes. The advertised size always refers to the diagonal, not the width or the height.
How are inches written?
With a double quote mark: 15.6" means 15.6 inches. A single quote indicates feet.
Are two screens of the same inch size identical?
Not necessarily. The inch measures the diagonal, and the area also depends on the screen’s aspect ratio.
How much is half an inch in millimetres?
Exactly 12.7 mm. A quarter inch is 6.35 mm and three eighths is 9.525 mm.
Need to calculate something else?
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