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Live dataUSD/CAD 1.3978U.S. 30-yr fixed 7.24%CA 5-yr posted 6.19%BoC rate 2.50%U.S. inflation 3.7%Express Entry cut-off 477 (Oct 28)U.S. gas $4.15/galUpdated Nov 3, 2026

Centimeters to Millimeters Converter

Convert centimeters (cm) to millimeters (mm) with the exact formula, worked examples and a full conversion chart.

Updated By TrueCalcu Editorial Team Sources
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How to convert centimeters to millimeters

To convert centimeters to millimeters, multiply the number of centimeters by 10.

Example: 2.5 cm = 25 mm.

There are exactly 10 millimeters in a centimeter.

Centimeters to Millimeters conversion chart

cmmm
0.25 cm2.5 mm
0.5 cm5 mm
0.75 cm7.5 mm
1 cm10 mm
1.5 cm15 mm
2 cm20 mm
2.5 cm25 mm
3 cm30 mm
3.5 cm35 mm
4 cm40 mm
4.5 cm45 mm
5 cm50 mm
6 cm60 mm
7 cm70 mm
8 cm80 mm
9 cm90 mm
10 cm100 mm
11 cm110 mm
12 cm120 mm
13 cm130 mm
14 cm140 mm
15 cm150 mm
16 cm160 mm
18 cm180 mm
20 cm200 mm
24 cm240 mm
25 cm250 mm
30 cm300 mm
32 cm320 mm
35 cm350 mm
40 cm400 mm
45 cm450 mm
50 cm500 mm
55 cm550 mm
60 cm600 mm
64 cm640 mm
65 cm650 mm
70 cm700 mm
75 cm750 mm
80 cm800 mm
85 cm850 mm
90 cm900 mm
100 cm1,000 mm
110 cm1,100 mm
120 cm1,200 mm
125 cm1,250 mm
128 cm1,280 mm
150 cm1,500 mm
175 cm1,750 mm
180 cm1,800 mm
200 cm2,000 mm
220 cm2,200 mm
250 cm2,500 mm
300 cm3,000 mm
400 cm4,000 mm
500 cm5,000 mm
750 cm7,500 mm
1,000 cm10,000 mm

Metric vs. U.S. customary units

The United States uses U.S. customary units — inches, feet, miles, pounds, gallons and degrees Fahrenheit — for most everyday purposes. Canada officially adopted the metric system in the 1970s, so road signs, weather forecasts, gas pumps and food labels use kilometers, degrees Celsius, liters and grams. In practice many Canadians still use feet and inches for height, pounds for body weight and square feet for homes, which is why conversions come up constantly on both sides of the border.

Exact conversion factors

Since 1959 the inch, foot, yard, mile and pound have been defined in metric terms, so these conversions are exact, not approximations:

  • 1 inch = 2.54 cm exactly, so 1 foot = 30.48 cm and 1 mile = 1.609344 km.
  • 1 pound = 0.45359237 kg exactly; 1 ounce = 28.349523125 g.
  • 1 U.S. gallon = 3.785411784 liters. The imperial gallon used in the U.K. is larger: 4.54609 liters.
  • 1 acre = 4,046.8564224 m², and 1 hectare = 10,000 m² (about 2.471 acres).

Temperature is different because the scales have different zero points: °F = °C × 9/5 + 32 and °C = (°F − 32) × 5/9. Water freezes at 0 °C (32 °F) and boils at 100 °C (212 °F) at sea level, and −40 is the same in both scales.

Quick mental shortcuts

  • Kilometers to miles: multiply by 0.6 (100 km ≈ 60 miles; the exact figure is 62.1).
  • Kilograms to pounds: double it and add 10% (70 kg → 140 + 14 = 154 lb).
  • Celsius to Fahrenheit: double it and add 30 for a rough estimate (20 °C → 70 °F; the exact answer is 68 °F).
  • Liters to U.S. gallons: divide by 4 for a quick estimate (40 L ≈ 10 gallons; exactly 10.57).

Cooking and recipe conversions

U.S. recipes measure by volume — cups, tablespoons and teaspoons — while Canadian and most international recipes use milliliters and grams. A U.S. cup is about 237 mL, but Canadian "metric" measuring cups hold 250 mL, so the difference adds up in baking. For flour, sugar and butter, weighing in grams is more accurate than cups because the density of each ingredient differs.

Popular conversions

Pick a conversion below for a dedicated page with the formula, worked examples and a complete conversion chart.

Tips for accurate conversions

Keep full precision until the final step and round only the answer — rounding intermediate numbers can add noticeable errors, especially in recipes, construction and engineering. Always check which gallon, ounce or ton a source means: U.S. and imperial units share names but not sizes, and a "fluid ounce" measures volume while an "ounce" of weight measures mass. For temperatures, remember that a temperature difference converts differently from a temperature reading: a change of 10 °C equals a change of 18 °F, without adding 32.

Popular unit conversions

Frequently asked questions

How many centimeters are in an inch?
Exactly 2.54 centimeters. To convert inches to centimeters, multiply by 2.54; to convert centimeters to inches, divide by 2.54.
How do I convert kg to pounds?
Multiply kilograms by 2.20462. For example, 70 kg × 2.20462 = 154.3 lb.
What is the formula for Celsius to Fahrenheit?
Multiply by 9/5 (1.8) and add 32. For example, 25 °C × 1.8 + 32 = 77 °F.
Is a U.S. gallon the same as a Canadian gallon?
No. Canada sells gas by the liter, but when gallons are mentioned in Canada they are sometimes imperial gallons (4.546 L), which are about 20% larger than U.S. gallons (3.785 L).
How many square feet are in a square meter?
About 10.764 square feet. A 1,000 sq ft home is roughly 92.9 m².

Sources & methodology

This calculator was last reviewed on November 2, 2026. Figures are based on the following official and primary sources:

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