CM to Inches Converter

What “cm to inches” means

Centimeters and inches both measure length, but they belong to different measurement systems. Centimeters are part of the metric system (base unit: meter). Inches are part of the imperial and US customary system (commonly grouped with feet and yards). A cm to inches converter helps you translate measurements from one system to the other without guessing or doing mental math.

The exact conversion: 1 inch = 2.54 cm

The centimeter-to-inch conversion is built on a fixed standard: one inch is defined as exactly 2.54 centimeters. Because it’s a definition (not an approximation), the conversion is exact. Any small differences you see across calculators usually come from rounding the final result.

How to convert centimeters to inches

The conversion is a simple division:

For example, 10 cm ÷ 2.54 ≈ 3.937 inches. If you’re measuring something physical, you’ll usually round the result to a practical number of decimals (or to the nearest fraction of an inch) depending on what you’re doing.

Common reasons people convert cm to inches

Height conversion

Many countries record height in centimeters, while others commonly use feet and inches. If you have a height like 170 cm, converting it to feet and inches makes it easier to read in imperial format: about 5 ft 6.9 in (often rounded to 5′7″).

Clothing and shoe size charts

Size charts often list garment measurements in centimeters, especially for international brands. Converting to inches helps when you’re comparing against an inch-based chart or measuring tape.

DIY, woodworking, and construction

Tools and materials can be labeled in either metric or imperial units depending on country and supplier. Accurate conversions help you plan cuts, clearances, and fittings without “off by a little” mistakes that add up.

Product dimensions and screens

Product listings may show dimensions in cm, but many buyers think in inches—especially for screens, monitors, and displays where diagonal size is traditionally given in inches.

How many inches is a centimeter?

Since 1 inch = 2.54 cm, one centimeter equals the reciprocal:

If you want a quick mental approximation, you can remember “about 0.39 inches per cm,” but for anything that needs precision, it’s better to use the exact division and round at the end.

Rounding: how many decimals do you need?

The “right” rounding depends on context:

• Everyday use: 2 decimals is usually enough (e.g., 66.93 in).
• Height: often rounded to the nearest tenth or to the nearest whole inch for readability.
• Manufacturing/tolerances: 3–4+ decimals may be needed depending on specification.
• Design layouts: you might round to 1/16 inch or 1/8 inch if you’re matching tools marked in fractions.

This converter lets you pick decimal places, and also choose a rounding rule (round, down, up) when you need a consistent direction.

CM to feet and inches: a practical format

Feet and inches are a common way to express human height and larger measurements. The process is:

1. Convert cm to inches: cm ÷ 2.54
2. Convert inches to feet: divide by 12
3. The remainder is the inches portion

The Feet + Inches tab does this automatically and shows total inches and total feet as well.

Fast reference conversions you’ll see often

Here are a few values people commonly look up:

• 10 cm ≈ 3.94 in
• 30 cm ≈ 11.81 in
• 50 cm ≈ 19.69 in
• 100 cm ≈ 39.37 in
• 150 cm ≈ 59.06 in
• 180 cm ≈ 70.87 in
• 200 cm ≈ 78.74 in

If you need a custom range (for a chart or a sizing guide), use the Conversion Table tab to generate a list with your chosen step.

Millimeters, centimeters, and inches

Sometimes you’ll see mm and cm used together. Remember:

• 1 cm = 10 mm
• 1 inch = 25.4 mm

This converter also outputs millimeters so you can quickly move between common metric sizes and inch-based measurements.

Tips for measuring accurately

Use the same reference point

When measuring objects, make sure your tape starts exactly at the edge. A small shift can create noticeable differences, especially after conversion and rounding.

Decide the rounding rule before you cut

If you’re converting for a cut length, rounding up vs rounding down changes the outcome. In many physical builds, it’s safer to round up slightly and trim, or to match the tolerance your project allows.

Check unit labels in product listings

Some listings mix units (for example: “Length 30cm / 12in”). If your converted number is far off from the listed number, it might be a labeling mistake or a different measurement method (like diagonal vs width).