Square Feet to Square Miles Converter
1 square foot ≈ 3.58700643e-8 square miles
1 square foot equals 3.58701e-8 square miles
How to convert square feet to square miles
Area factors are squared length factors: 1 ft² = (0.3048 m)². The acre here uses international feet; historic US survey acres differ slightly.
mi² = ft² × 3.587006428e-8One square foot is 3.587006428e-8 square miles, so a single multiplication converts any value.
0.000000358701 mi² ≈ 10 × 3.587006428e-8Square feet to square miles conversion table
Common values in square feet, converted to square miles.
| Square feet (ft²) | Square miles (mi²) |
|---|---|
| 1 | 3.5870064e-8 |
| 2 | 7.1740129e-8 |
| 3 | 0.00000010761019 |
| 4 | 0.00000014348026 |
| 5 | 0.00000017935032 |
| 10 | 0.00000035870064 |
| 20 | 0.00000071740129 |
| 25 | 0.00000089675161 |
| 50 | 0.0000017935032 |
| 100 | 0.0000035870064 |
| 250 | 0.0000089675161 |
| 500 | 0.000017935032 |
| 1,000 | 0.000035870064 |
About these units
square footft²
The area of a square one foot on each side. The standard unit for US floor area.
square milemi²
Exactly 640 acres. Used for county and country areas.
Sources and precision
Table results are rounded to 8 significant digits; formula constants may be rounded to 10. Worked example answers use 6 significant digits. The converter starts at 6 significant digits and lets you change display precision. Calculations use the stored factors without intermediate rounding. Exact unit definitions do not make an input measurement more precise; conventional and measured factors follow the assumptions stated here.