Inches to CM Conversion: Formula, Table & Quick Reference

Whether you’re buying furniture from an overseas retailer, working on a DIY project with mixed-unit plans, or checking clothing sizes, converting between inches and centimeters is one of the most common unit conversions. Here’s the formula, a complete reference table, and the conversions you’ll use most often.

The Conversion Formula

Centimeters = Inches × 2.54
Inches = Centimeters / 2.54

The 2.54 factor is exact — one inch is defined as precisely 2.54 centimeters. This isn’t a rounded approximation; it’s the official definition since 1959.

Examples:

• 12 inches = 12 × 2.54 = 30.48 cm
• 5.5 inches = 5.5 × 2.54 = 13.97 cm
• 72 inches (6 ft) = 72 × 2.54 = 182.88 cm

Complete Conversion Table: 1 to 36 Inches

Inches	CM	Inches	CM	Inches	CM
1	2.54	13	33.02	25	63.50
2	5.08	14	35.56	26	66.04
3	7.62	15	38.10	27	68.58
4	10.16	16	40.64	28	71.12
5	12.70	17	43.18	29	73.66
6	15.24	18	45.72	30	76.20
7	17.78	19	48.26	31	78.74
8	20.32	20	50.80	32	81.28
9	22.86	21	53.34	33	83.82
10	25.40	22	55.88	34	86.36
11	27.94	23	58.42	35	88.90
12	30.48	24	60.96	36	91.44

Fraction Conversions

Many measurements use fractions of inches. Here are common fractional conversions:

Fraction	Decimal	CM
1/8”	0.125	0.318
1/4”	0.250	0.635
3/8”	0.375	0.953
1/2”	0.500	1.270
5/8”	0.625	1.588
3/4”	0.750	1.905
7/8”	0.875	2.223

For compound measurements like 5 3/4 inches: convert to decimal first (5.75), then multiply: 5.75 × 2.54 = 14.605 cm.

Common Objects: Inches and CM Reference

Knowing the approximate size of everyday items helps you visualize measurements:

Object	Inches	CM
Credit card (width)	3.37”	8.56
Dollar bill (length)	6.14”	15.60
Letter paper (width)	8.5”	21.59
Letter paper (height)	11”	27.94
Standard ruler	12”	30.48
Laptop screen (13”)	13” diagonal	33.02
Carry-on luggage (height)	22”	55.88
TV screen (55”)	55” diagonal	139.70
Standard door (width)	36”	91.44
Standard door (height)	80”	203.20

Quick mental math tip: For rough conversions without a calculator, multiply inches by 2.5 and add 1% of the original number. For 8 inches: 8 × 2.5 = 20, plus 1% of 8 ≈ 0.08, so roughly 20.1 cm (actual: 20.32). Close enough for quick estimates.

Calculate instantly with our Inches to CM Converter.