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Inches to Centimeters Converter
↔ Convert cm to in instead

Common Conversions

in cm
0.25 0.635
0.5 1.27
1 2.54
2 5.08
3 7.62
4 10.16
6 15.24
8 20.32
10 25.4
12 30.48
24 60.96

Why this conversion matters in chemistry

Quarter-inch and eighth-inch OD tubing is the default for gas lines and compression fittings in most US-built labs, and a six-inch petri dish is a standard microbiology consumable. Everything downstream of the fitting — bench glassware, protocol metadata, published literature — tends to describe the same parts in centimeters. Multiplying inches by 2.54 is the bridge: quarter-inch tubing is 0.635 cm, a six-inch petri dish is 15.24 cm. The factor is exact (pinned by international agreement in 1959), so no precision is lost. Same physical length, just indexed through a different historical scale.

Formula

cm = in × 2.54

Worked Examples

1 in = 2.54 cm

The defining equivalence. Exact by international agreement since 1959.

12 in = 30.48 cm

One foot, written two ways. Useful anchor when a drawing needs to cross an imperial/metric boundary.

0.25 in = 0.635 cm

A quarter-inch OD tubing — one of the most common sizes for gas lines and compression fittings.

6 in = 15.24 cm

A standard petri dish diameter. The classic benchtop vessel for microbiology and many chemistry crystallization setups.

Frequently Asked Questions

How do I convert inches to centimeters?
Multiply by 2.54. So 6 in becomes 15.24 cm, 12 in becomes 30.48 cm. The factor is exact — you don't need to carry extra significant figures.
Is the conversion exact?
Yes. Since 1959, the international inch has been defined as exactly 2.54 cm by agreement. Before that, slightly different definitions existed in different countries, but the modern inch is unambiguous.
When do chemists use inches?
On US-sourced lab equipment. Common examples: 1/4- and 1/8-inch tubing for gas lines and compression fittings, 1/2-inch preparative columns, inch-labeled glassware from older US vendors. The rest of the chemistry paperwork almost always gets converted to cm.
How do inches, cm, and mm relate?
1 inch is exactly 2.54 cm or 25.4 mm. Going the other way, 1 cm is 10 mm or about 0.394 inches. Two decimal places of centimeters and one of millimeters cover everything a chemistry lab cares about.