Square Inches to Square Centimeters Converter (in² to cm²)

How to convert square inches to square centimeters

To convert square inches to square centimeters, multiply the number of square inches by 6.452.

Example: 10 in² = 64.516 cm².

One square inch is exactly 6.4516 square centimeters.

Common in² to cm² conversions

1 in² = 6.452 cm²
10 in² = 64.516 cm²
100 in² = 645.16 cm²

Square Inches to Square Centimeters conversion chart

in²	cm²
0.25 in²	1.613 cm²
0.5 in²	3.226 cm²
0.75 in²	4.839 cm²
1 in²	6.452 cm²
1.5 in²	9.677 cm²
2 in²	12.903 cm²
2.5 in²	16.129 cm²
3 in²	19.355 cm²
3.5 in²	22.581 cm²
4 in²	25.806 cm²
4.5 in²	29.032 cm²
5 in²	32.258 cm²
6 in²	38.71 cm²
7 in²	45.161 cm²
8 in²	51.613 cm²
9 in²	58.064 cm²
10 in²	64.516 cm²
11 in²	70.968 cm²
12 in²	77.419 cm²
13 in²	83.871 cm²
14 in²	90.322 cm²
15 in²	96.774 cm²
16 in²	103.23 cm²
18 in²	116.13 cm²
20 in²	129.03 cm²
24 in²	154.84 cm²
25 in²	161.29 cm²
30 in²	193.55 cm²
32 in²	206.45 cm²
35 in²	225.81 cm²
40 in²	258.06 cm²
45 in²	290.32 cm²
50 in²	322.58 cm²
55 in²	354.84 cm²
60 in²	387.1 cm²
64 in²	412.9 cm²
65 in²	419.35 cm²
70 in²	451.61 cm²
75 in²	483.87 cm²
80 in²	516.13 cm²
85 in²	548.39 cm²
90 in²	580.64 cm²
100 in²	645.16 cm²
110 in²	709.68 cm²
120 in²	774.19 cm²
125 in²	806.45 cm²
128 in²	825.8 cm²
150 in²	967.74 cm²
175 in²	1,129 cm²
180 in²	1,161.3 cm²
200 in²	1,290.3 cm²
220 in²	1,419.4 cm²
250 in²	1,612.9 cm²
300 in²	1,935.5 cm²
400 in²	2,580.6 cm²
500 in²	3,225.8 cm²
750 in²	4,838.7 cm²
1,000 in²	6,451.6 cm²

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:

NIST – Handbook 44, Appendix C: General Tables of Units of Measurement

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