Convert square miles to square feet

One square mile equals 27,878,400 square feet. To convert any number of square miles to square feet, multiply by 27,878,400.

The converter above works in both directions and updates as you type. Below you will find the formula, a worked example and a reference table of common values.

Area conversions carry a trap that catches people who are perfectly comfortable with length: the factor is squared. There are 3.28 feet in a metre but 10.76 square feet in a square metre, and using the linear factor is the most common error in property arithmetic. Beyond that, land is measured in whatever the local convention prescribes — acres, hectares, and across South Asia bigha, katha and gaj — so the same plot is routinely described in two units that need reconciling.

square miles to square feet formula

To go the other way, use square mile = square foot ÷ 27,878,400.

About these units

A square mile is 640 acres, which is why a US Public Land Survey section — one square mile — divides so neatly into quarter-sections of 160 acres.

The square foot remains the standard for property area in the US, India and much of the Middle East. There are 10.764 square feet in a square metre — not 3.28, a mistake that comes from squaring the linear factor only once.

Square Mile is also written square miles, sq mi and mi2. Square Foot is also written square feet, sq ft, sqft, ft2 and ft^2.

Sources

1. National Bureau of Standards, "Refinement of Values for the Yard and the Pound", Federal Register, 1 July 1959 — the international yard as exactly 0.9144 m and the avoirdupois pound as exactly 0.45359237 kg.