Square Miles to Square Kilometers Converter

Common questions

How many square kilometers are in a square mile?

2.589988110336 km² exactly, which this page prints as 2.58998811034 at twelve significant digits. The multiplication scales cleanly: 0.5 mi² is 1.29499405517 km², 2 mi² is 5.17997622067 km², 5 mi² is 12.9499405517 km², 10 mi² is 25.8998811034 km², 100 mi² is 258.998811034 km² and 1,000 mi² is 2,589.98811034 km².

What is the formula for square miles to square kilometers?

Square kilometres = square miles × 2.589988110336, and square miles = square kilometres × 0.386102158542 in the other direction, which is the same as dividing by 2.589988110336. So 1 km² is 0.386102158542 mi², 100 km² is 38.6102158542 mi² and 500 km² is 193.051079271 mi². The swap button between the two boxes reverses the pair, which turns this into a square kilometers to square miles converter without a reload.

Why is the factor 2.59 and not 1.609344?

Because area scales as the square of length. A mile is 1.609344 km, and 1.609344 squared is 2.589988110336, so every square mile is nearly two and a half square kilometres even though a mile is only a little over one and a half kilometres. The same squaring runs the other way: a kilometre is 0.621371192237 miles, and that squared is the 0.386102158542 square miles this page gives for 1 km².

How many acres and square feet are in a square mile?

Exactly 640 acres and exactly 27,878,400 square feet, both of which sit in the list under the answer, along with 3,097,600 square yards, 4,014,489,600 square inches, 258.998811034 hectares and 2,589,988.11034 square metres. Those whole numbers are not rounding: the acre, the foot and the mile are defined against each other, so an acre comes back as 0.0015625 mi² with nothing left over.

Which mile is it, the international mile or the US survey mile?

The international mile of exactly 1,609.344 metres, which is why 1 mi² reads 2.58998811034 km². The older US survey mile, built on the survey foot the United States retired at the end of 2022, is 1,609.3472186944 m, longer by two parts per million, so a survey square mile works out near 2.589998470319 km². That is four parts per million larger, about 10.36 square metres in every square mile: invisible on a city, worth knowing on an old land record.

How big is a section or a township in square kilometers?

A section of the US Public Land Survey is one square mile, so 640 acres, and this page reads it as 2.58998811034 km². A township of 36 sections is 36 square miles, which converts to 93.2395719721 km². Type either figure in the From box, or type the acreage and pick Acre in the From menu, since 640 acres is the same square mile from the other side.

Where do the units sit in the list under the answer?

The list shows every other unit in the area category and leaves out the one you are converting from, so here it reads square centimetre, square metre, hectare, square kilometre, square inch, square foot, square yard and acre, with the square kilometre appearing both as the headline and as a row. The readout strip carries an Uncommon units switch labelled Show 1 more, which adds the square millimetre: one square mile is 2,589,988,110,340 mm².

Why does the page open on square miles and square kilometres when I last converted something else?

Because a page that names a pair should show that pair. This one sets Square mile and Square kilometre on arrival, ahead of whatever the converter last remembered, and it leaves the main unit converter's own pair alone: go back there and it is still on the units you left it on. The number you last typed does travel with you, along with the uncommon units switch, since that is usually the figure you are still working on.