Convert Square Miles to Acres
Convert Square Miles to Acres instantly. 1 Square Mile (mi²) equals 640 Acres (ac).
Square Miles to Acres conversion table
| Square Miles (mi²) | Acres (ac) |
|---|---|
| 1 mi² | 640 ac |
| 2 mi² | 1,280 ac |
| 3 mi² | 1,920 ac |
| 5 mi² | 3,200 ac |
| 10 mi² | 6,400 ac |
| 20 mi² | 12,800 ac |
| 50 mi² | 32,000 ac |
| 100 mi² | 64,000 ac |
| 500 mi² | 320,000 ac |
| 1,000 mi² | 640,000 ac |
1 Square Mile = 640 Acres · multiply Square Miles by 640
About converting Square Miles to Acres
Square Miles (mi²) and Acres (ac) are both units of area, so converting between them is a single multiplication: multiply your Square Miles figure by 640. Ten Square Miles comes to 6,400 Acres, and a hundred works out at 64,000 Acres.
Rule of thumb: going from Square Miles to Acres multiplies, so the figure always grows — one Square Mile is already 640 Acres. If your answer came out smaller, you have the conversion the wrong way round.
What is a Square Mile?
A square mile is the area of a square one mile on a side, and in the United States it is the standard way to state the size of anything large: counties, states, metropolitan areas, wildfires and watersheds are all reported in square miles, along with population density in people per square mile. Elsewhere the same figure is given in square kilometers, which is why one lake can carry two very different-looking numbers depending on the source. The unit is literally built into the American landscape — the Public Land Survey System carved much of the country into square-mile sections, which is why the Midwest is a grid of mile-spaced roads.
What is an Acre?
The acre is the awkward number in the system, and the reason is that it was never a piece of geometry: it was the area a man with a single ox could plough in a day. That gave it a shape as well as a size — one furlong long by one chain wide, the furlong being the length of the furrow before the team was turned around. Formalised as 4,840 square yards, it never rounded off to anything tidy, and nobody minded, because it described a day’s work. It is still the standard unit for land in the US and for farmland and property in the UK and India.
To put both in perspective: Manhattan is roughly 23 square miles, while a football pitch is a bit over an acre.
The converter above updates as you type, and the table lists common values for quick reference. Need the opposite direction? Use the Acres to Square Miles converter, or browse all Area converters.
Frequently asked questions
How many Acres are in one Square Mile?
There are 640 Acres in one Square Mile.
How do I convert Square Miles to Acres?
Multiply the number of Square Miles by 640. For example, 10 Square Miles = 6,400 Acres.
What is 100 Square Miles in Acres?
100 Square Miles is equal to 64,000 Acres.
How do I convert Acres to Square Miles?
Multiply the Acres value by 0.001563 (or divide by 640).
Is this Square Miles to Acres conversion exact?
Yes, exactly. Both units are fixed against the same base by definition, and 1 Square Mile = 640 Acres is the complete value — nothing is rounded away.
What is a Square Mile?
A square mile is the area of a square one mile on a side, and in the United States it is the standard way to state the size of anything large: counties, states, metropolitan areas, wildfires and watersheds are all reported in square miles, along with population density in people per square mile. Elsewhere the same figure is given in square kilometers, which is why one lake can carry two very different-looking numbers depending on the source. The unit is literally built into the American landscape — the Public Land Survey System carved much of the country into square-mile sections, which is why the Midwest is a grid of mile-spaced roads.
What is an Acre?
The acre is the awkward number in the system, and the reason is that it was never a piece of geometry: it was the area a man with a single ox could plough in a day. That gave it a shape as well as a size — one furlong long by one chain wide, the furlong being the length of the furrow before the team was turned around. Formalised as 4,840 square yards, it never rounded off to anything tidy, and nobody minded, because it described a day’s work. It is still the standard unit for land in the US and for farmland and property in the UK and India.