Acres to Square Feet Calculator - Convert Acres to ft²

About the Acres to Square Feet Calculator

The acre is the everyday unit for land in the United States and still widely used in the UK and other English-speaking countries, for house lots, farms, parks and building sites. Square feet, meanwhile, are how buildings and smaller plots are measured. To work out how much of a lot a house will cover, compare a plot with a floor plan, or understand a listing that mixes the two, you need to know how many square feet an acre holds.

This acres to square feet calculator converts acres to square feet exactly. It also gives the area in square metres and hectares, in square yards (and square miles for large areas), and the side of a square plot of the same area to help picture it.

How to Use the Acres to Square Feet Calculator

Enter the area in acres. Fractions such as 0.25 or 1.5 are fine.

The square feet appear straight away, with the metric area, square yards and the size of an equal square.

The Formula

  square feet   = acres × 43,560
  square yards  = acres × 4,840
  square metres = acres × 4,046.8564224
  hectares      = square metres ÷ 10,000

The acre has been exactly 43,560 square feet since the foot was standardised. It comes from the old English measure of a strip of land one furlong (660 feet) long and one chain (66 feet) wide: 660 × 66 = 43,560.

Step-by-Step Example

One acre.

  1 × 43,560 = 43,560 ft²
  1 × 4,046.8564224 = 4,046.86 m²
  side of an equal square = √43,560 = 208.71 ft (63.6149 m)

A quarter-acre lot.

  0.25 × 43,560 = 10,890 ft²

A quarter acre is 10,890 square feet, about 1,011.71 m². If square, it would measure about 104.4 feet on each side.

Quick Reference

  1/8 acre   =   5,445 ft²      2 acres   =  87,120 ft²
  1/4 acre   =  10,890 ft²      5 acres   = 217,800 ft²
  1/3 acre   =  14,520 ft²      10 acres  = 435,600 ft²
  1/2 acre   =  21,780 ft²      40 acres  = 1,742,400 ft²
  1 acre     =  43,560 ft²      640 acres = 1 square mile

House Lots and Building Coverage

Residential lots in American suburbs are often described in fractions of an acre: an eighth-acre lot is 5,445 ft², a quarter-acre lot 10,890 ft². To see how much of the lot a house occupies, compare its footprint — the ground floor area, not the total floor area — with the lot size. A 1,800 ft² single-storey house on a quarter-acre lot covers about 16.5 percent of the land, leaving the rest for garden, driveway and setbacks. Local planning rules often limit this coverage, so the conversion matters when planning an extension.

Farms and Larger Areas

Farms and ranches are measured in tens, hundreds or thousands of acres. The US Public Land Survey divided much of the country into sections of one square mile, 640 acres, split into quarter sections of 160 acres — the size of the classic homestead grant. A 40-acre field, a quarter of a quarter section, is 1,742,400 square feet, about 16.19 hectares.

Acres and Hectares

Most of the world measures land in hectares, 10,000 square metres each. An acre is about 0.404686 hectares, and a hectare about 2.47105 acres. When comparing land prices or farm sizes internationally, convert both figures to the same unit first: a price per acre is always lower than the equivalent price per hectare, by a factor of about 2.47.

Measuring an Irregular Plot

Real plots are rarely neat rectangles. For a four-sided plot with roughly parallel sides, average the two opposite lengths and multiply by the average of the other two for a fair estimate. For more complex shapes, divide the plot into rectangles and triangles, calculate each area in square feet — half the base times the height for a triangle — and add them up before converting to acres by dividing by 43,560. Property deeds and survey plans usually state the official area, which is the figure to use for legal and tax purposes; your own measurements are for planning and estimating.

Picturing an Acre

An acre is a little smaller than an American football field: the playing area between the goal lines is 300 by 160 feet, 48,000 square feet, about 1.1 acres, and with end zones about 1.32 acres. It is a little over half the size of a full-size soccer pitch, and roughly 15 tennis courts laid side by side. In homes, it is about the floor area of 20 to 25 typical American houses, which helps when imagining how many homes a new development of a few acres might hold once roads and gardens are added.

Understanding Your Result

The headline is the area in square feet.

The metric line gives square metres and hectares.

The square yards line gives square yards, and square miles for 64 acres or more.

The equal square line gives the side of a square plot with the same area, in feet and metres.

When Should You Use This Calculator?

Use it to understand house lot sizes and compare them with floor areas.

Use it to plan building footprints, gardens, fences and landscaping.

Use it for farm, ranch and field sizes.

Use it to compare land listings given in acres, square feet or metric units.

Common Mistakes

Assuming an acre is a square. Any shape of 43,560 ft² is an acre, however long or narrow.

Using 40,000 or 44,000 as a round number. The exact figure is 43,560.

Confusing floor area with footprint. Lot coverage uses the ground floor only.

Mixing acres and hectares. A hectare is about two and a half acres.

Forgetting setbacks and easements. Not all of a lot is usable for building, so check local rules before planning.