Square Feet to Acres Calculator
Convert between square feet and acres. 1 acre = 43,560 square feet. Useful for property listings, lot sizing, and land valuation.
Square Feet ⇌ Acres Converter
The conversion factor
1 acre = 43,560 square feet, exactly. This number comes from historic measurement: an acre was originally a chain (66 ft) by a furlong (660 ft) = 43,560 sq ft.
To convert sq ft → acres: divide by 43,560. To convert acres → sq ft: multiply by 43,560.
Common lot sizes
0.10 acre = 4,356 sq ft (small urban lot). 0.25 acre = 10,890 sq ft (typical suburban quarter-acre). 0.50 acre = 21,780 sq ft (larger suburban). 1 acre = 43,560 sq ft. 2 acres = 87,120 sq ft. 5 acres = 217,800 sq ft. 10 acres = 435,600 sq ft.
For reference: a US football field (100 yd × 53.3 yd, including end zones at 120 × 53.3 yd) is about 1.32 acres or 57,600 sq ft.
Why 43,560 — origin of the acre
1 acre = exactly 43,560 square feet. The number isn't arbitrary — it's the area defined as one furlong (660 ft) by one chain (66 ft). 660 × 66 = 43,560.
The acre originated in medieval England as the area one yoke of oxen could plow in a day. It's still the standard land measurement in the US, UK, Canada, Australia, and other Commonwealth-influenced countries.
Common conversions: 1 acre = 4,047 m² = 4,840 sq yd = 0.4047 hectares. Half acre = 21,780 sq ft. Quarter acre = 10,890 sq ft. 1/10 acre = 4,356 sq ft. 1/8 acre = 5,445 sq ft.
What different lot sizes look like
1/10 acre (~65 × 67 ft): townhouse lot.
1/8 acre (~65 × 84 ft): small urban single-family lot.
1/4 acre (~105 × 105 ft, or 80 × 136 ft): typical American suburban lot.
1/3 acre (~121 × 120 ft): generous suburban lot.
1/2 acre (~148 × 148 ft): executive suburban / large lot subdivision.
1 acre (~209 × 209 ft): rural-edge property, exclusive large-lot neighborhoods.
2 acres: rural residential, hobby farm.
5 acres: small homestead, equestrian property.
10 acres (660 × 660 ft): rural homestead, small ranch.
Football field (with end zones): about 1.32 acres. Without end zones: about 1.1 acres.
Acreage in real estate and zoning
Lot size: total property area, listed on every real estate listing.
Buildable area: lot area minus setbacks (typically 10-30 ft from each property line) and easements. Often 50-70% of total lot area.
Floor Area Ratio (FAR): the ratio of building square footage to lot square footage. Residential zoning typically allows 0.3-0.5 FAR. A 10,000 sq ft lot at 0.4 FAR allows 4,000 sq ft of building.
Density limits in zoning: single-family typically 4-12 units per acre. Townhouse 12-30. Multi-family 30-200+.
When evaluating a property: check setbacks, easements, FAR, height restrictions, and any environmental or historic overlays. These can dramatically reduce buildable area despite generous lot acreage.
Pro tips
Real estate rounds heavily
A "0.25 acre lot" might be 0.247 (10,762 sq ft) or 0.253 (11,021 sq ft). Use the actual figure from the plat or deed for any calculation that matters.
Don't confuse with hectares
1 hectare = 10,000 sq m = 107,639 sq ft = 2.47 acres. Hectares are the metric standard for land area outside the US.
Sections and acres
A "section" of land in US public land surveying is 1 mile × 1 mile = 640 acres = 27,878,400 sq ft.
Use the calculator above for irregular lots
For irregular property shapes, use the multi-segment calculator to sum up rectangles. The result panel shows acres automatically.