Square Miles to Square Kilometers Converter (mi² to km²)

How to convert square miles to square kilometers

To convert square miles to square kilometers, multiply the number of square miles by 2.59.

Example: 10 mi² = 25.9 km².

One square mile is about 2.59 square kilometers.

Square Miles to Square Kilometers conversion chart

mi²	km²
0.25 mi²	0.6475 km²
0.5 mi²	1.295 km²
0.75 mi²	1.942 km²
1 mi²	2.59 km²
1.5 mi²	3.885 km²
2 mi²	5.18 km²
2.5 mi²	6.475 km²
3 mi²	7.77 km²
3.5 mi²	9.065 km²
4 mi²	10.36 km²
4.5 mi²	11.655 km²
5 mi²	12.95 km²
6 mi²	15.54 km²
7 mi²	18.13 km²
8 mi²	20.72 km²
9 mi²	23.31 km²
10 mi²	25.9 km²
11 mi²	28.49 km²
12 mi²	31.08 km²
13 mi²	33.67 km²
14 mi²	36.26 km²
15 mi²	38.85 km²
16 mi²	41.44 km²
18 mi²	46.62 km²
20 mi²	51.8 km²
24 mi²	62.16 km²
25 mi²	64.75 km²
30 mi²	77.7 km²
32 mi²	82.88 km²
35 mi²	90.65 km²
40 mi²	103.6 km²
45 mi²	116.55 km²
50 mi²	129.5 km²
55 mi²	142.45 km²
60 mi²	155.4 km²
64 mi²	165.76 km²
65 mi²	168.35 km²
70 mi²	181.3 km²
75 mi²	194.25 km²
80 mi²	207.2 km²
85 mi²	220.15 km²
90 mi²	233.1 km²
100 mi²	259 km²
110 mi²	284.9 km²
120 mi²	310.8 km²
125 mi²	323.75 km²
128 mi²	331.52 km²
150 mi²	388.5 km²
175 mi²	453.25 km²
180 mi²	466.2 km²
200 mi²	518 km²
220 mi²	569.8 km²
250 mi²	647.5 km²
300 mi²	777 km²
400 mi²	1,036 km²
500 mi²	1,295 km²
750 mi²	1,942.5 km²
1,000 mi²	2,590 km²

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

Spotted an error? Tell us and we'll fix it quickly. Read how we build and update our tools in our editorial policy.

Embed this calculator on your website

Free for blogs, real-estate sites, employers and newsletters. Copy this code into your page — it always shows the latest rates and rules.

<iframe src="https://truecalcu.com/embed/unit-converter" title="Unit Converter" width="100%" height="720" style="border:0;border-radius:16px;max-width:900px" loading="lazy"></iframe>
<p style="font-size:13px"><a href="https://truecalcu.com/unit-converter">Unit Converter</a> by TrueCalcu</p>