Calculate the acreage of any parcel from its length and width, shape dimensions, or a known area, with instant conversions to square feet, hectares, and square miles.
Acreage Formula
Acreage starts with the area of the parcel in square feet and divides by the number of square feet in one acre:
Acres = Area (sq ft) / 43,560
The area itself depends on the shape you measure. The calculator supports several shapes and two reverse modes:
Rectangle Area = Length x Width
Triangle Area = (Base x Height) / 2
Trapezoid Area = ((Side1 + Side2) / 2) x Height
Circle Area = pi x Radius^2
Missing Rectangle Side = (Target Acres x 43,560) / Known Side
Equal Square Side = sqrt(Target Acres x 43,560)
- Area (sq ft): the surface area of the parcel measured in square feet before converting to acres.
- 43,560: the fixed number of square feet in one acre.
- Length and Width: the two sides of a rectangular or square parcel.
- Base and Height: for a triangle, the base and the perpendicular height measured at a right angle to that base.
- Side1 and Side2: the two parallel sides of a trapezoid, with Height the perpendicular distance between them.
- Radius: the distance from the center of a circular parcel to its edge.
- Target Acres: the acreage you want when solving for a missing side or an equal square side.
- Known Side: the one rectangle side you already know when solving for the other.
In total acreage mode you pick a shape, enter its dimensions in feet, yards, meters, or kilometers, and the calculator converts the area to acres along with square feet, square meters, hectares, square yards, and square miles. The known area option lets you skip the shape math and convert an area you already have. Advanced options can subtract an excluded area, such as a pond or easement, and estimate land value from a price per acre. The missing side mode finds the second side of a rectangle when you know the target acreage and one side, and the square side mode returns the length of each side of a square parcel of a given acreage.
Common Parcel Sizes and Conversions
These reference values help you sanity check a result before you rely on it.
| Acres | Square Feet | Square Meters | Hectares |
|---|---|---|---|
| 0.25 | 10,890 | 1,012 | 0.101 |
| 0.5 | 21,780 | 2,023 | 0.202 |
| 1 | 43,560 | 4,047 | 0.405 |
| 5 | 217,800 | 20,234 | 2.023 |
| 10 | 435,600 | 40,469 | 4.047 |
| 640 | 27,878,400 | 2,589,988 | 258.999 |
A square parcel of one acre measures about 208.7 feet on each side. A section of land, used in many rural property descriptions, is 640 acres or one square mile.
| Shape | Inputs You Measure | Area Step |
|---|---|---|
| Rectangle or square | Length, Width | Length x Width |
| Triangle | Base, Height | (Base x Height) / 2 |
| Trapezoid | Two parallel sides, Height | ((Side1 + Side2) / 2) x Height |
| Circle | Radius | pi x Radius^2 |
Example Problems
Example 1: Rectangular lot. A lot measures 660 feet long and 330 feet wide. Multiply to get the area: 660 x 330 = 217,800 square feet. Divide by 43,560: 217,800 / 43,560 = 5 acres.
Example 2: Missing side from a target acreage. You want a 1 acre rectangle and one side is already 145 feet. Convert the target to square feet: 1 x 43,560 = 43,560 square feet. Divide by the known side: 43,560 / 145 = 300.4 feet for the other side.
Frequently Asked Questions
How many square feet are in an acre? One acre is exactly 43,560 square feet. This is the figure you divide by to turn any area in square feet into acres, and it is the same whether the parcel is a square, a rectangle, or an irregular shape.
How do I find the acreage of an irregular parcel? Break the parcel into shapes the calculator supports, such as rectangles and triangles, find the acreage of each piece, and add them together. If you already know the total area from a survey or map tool, use the known area option and the calculator converts it directly to acres.
What size is one acre on the ground? One acre can take any shape, so it has no fixed length and width. As a square it is about 208.7 feet on each side. As a long, narrow strip it might be 43,560 feet long and 1 foot wide. The acreage depends only on the total area, not the proportions.
