Acreage Calculator
Acreage Calculator
Enter Your Dimensions
Select a shape, enter your land dimensions, and the calculator will instantly show the area in acres, square feet, hectares, and more.
Compute land area in acres for any shape — rectangle, circle, triangle, and more
Whether you are buying a piece of land, planning a fence, dividing a property among heirs, or simply curious about how large a parcel really is, knowing the acreage is the essential first step. An acreage calculator takes the dimensions of your plot — length and width, radius, or a set of vertex coordinates — and converts the result into the most useful land-measurement units used in the United States and worldwide. An acre is the standard unit of land measurement in the United States, Canada, the United Kingdom, and many other countries. By definition, one acre equals exactly 43,560 square feet, 4,840 square yards, or approximately 4,047 square meters. Historically, an acre was the amount of land that one man could plow in a single day using a team of oxen — roughly a strip measuring 1 chain (66 feet) wide and 1 furlong (660 feet) long. Today it remains the workhorse of real estate and agriculture alike. Our calculator goes well beyond a simple rectangle multiplier. You can calculate the area of six common geometric shapes — rectangle, triangle, circle, trapezoid, ellipse, and parallelogram — as well as irregular polygons by entering a list of (x, y) vertex coordinates. The shoelace formula handles any closed polygon no matter how irregular its shape, making it ideal for odd-shaped lots with multiple corners. In addition to the primary result in acres, the tool outputs the full conversion table: square feet, square yards, square meters, hectares, square miles, and square kilometers. It calculates the perimeter for shapes where a formula is available (rectangle, circle, ellipse), then uses that perimeter to estimate fencing costs across five common fencing materials — chain-link, wood privacy, vinyl, wrought iron or aluminum, and split-rail. You can also enter an optional price per unit (per acre, per square foot, per square meter, or per hectare) to get an instant total land cost. The lot subdivision feature lets you split your total parcel into any number of equal portions and see the dimensions of each parcel — useful when dividing an estate, planning a subdivision, or checking legal minimum lot sizes. Quick preset buttons for typical suburban lots (0.25 acres), half-acre, 1-acre, and 5-acre farm fields let you load common configurations in a single click. A side-by-side comparison mode lets you measure two rectangular plots simultaneously and see the difference in acres. A land context bar chart compares your parcel against everyday reference points: a football field (1.32 acres), a soccer pitch (1.98 acres), a basketball court, a tennis court, and a city block — giving you a vivid sense of scale. Finally, an automatic walking time estimate calculates how long it would take to walk the perimeter at an average pace of 3 miles per hour, a quick reality check for anyone assessing a rural property. All calculations run entirely in your browser — no data is sent to any server. You can export the results as a CSV file, copy them to your clipboard, or print a clean summary.
Understanding Acreage
What Is an Acre?
An acre is a unit of area equal to 43,560 square feet, or 4,840 square yards, or approximately 4,047 square meters. It originated in medieval England as the amount of land one man could plow in a day with a yoke of oxen — a strip 1 chain wide (66 feet) by 1 furlong long (660 feet). Despite its agricultural origins, the acre remains the primary unit for measuring land in the United States, United Kingdom, Canada, and several other countries. One square mile contains exactly 640 acres. A hectare — the metric equivalent widely used in continental Europe, Australia, and elsewhere — equals 2.471 acres. Understanding acreage is essential for real estate transactions, agricultural planning, zoning compliance, and any project involving land subdivision or fencing.
How Is Acreage Calculated?
The basic formula for a rectangular plot is: Acres = (Length × Width) / 43,560, where length and width are measured in feet. For other units, you first convert each dimension to feet before applying the formula — or equivalently, multiply by the appropriate conversion factor. For non-rectangular shapes the area formula changes: triangles use 0.5 × base × height; circles use π × r²; trapezoids use ((base1 + base2) / 2) × height; ellipses use π × semi-major × semi-minor; parallelograms use base × height. For irregular polygons with known vertex coordinates the shoelace (Gauss) formula computes the exact area as half the absolute value of the sum of cross-products of consecutive vertex pairs. In every case the resulting area in square feet is divided by 43,560 to obtain acres.
Why Acreage Matters
Knowing the precise acreage of a parcel affects nearly every decision in land ownership and real estate. Property taxes are assessed per acre in many jurisdictions; a half-acre lot may fall into a completely different tax bracket than a three-quarter-acre lot. Zoning codes specify minimum lot sizes in acres — many suburban zones require at least 0.25 acres per dwelling. Agricultural subsidies, crop insurance, and government programs are calculated per acre. Fencing a property requires knowing the perimeter, which depends on the shape and area. Land sales are priced per acre, so an error in acreage calculation can mean thousands of dollars in a transaction. Even for non-commercial purposes — camping, hiking, gardening, or estate planning — understanding area in relatable units helps you visualize and plan effectively.
Surveyor Units: Chains and Rods
Traditional land surveying in the United States and United Kingdom relied on the Gunter's chain as the fundamental unit. One chain equals 66 feet or 4 rods (also called perches). One square chain equals 4,356 square feet, and 10 square chains equal exactly 1 acre — a relationship that made the acre extremely convenient in surveys conducted with a chain. One rod equals 16.5 feet, so one square rod equals 272.25 square feet, and 160 square rods equal 1 acre. You will still encounter these units in older legal property descriptions, deeds, and government land grants in the Public Land Survey System (PLSS) used throughout the western United States. Our calculator supports chains and rods as input units alongside feet, yards, meters, inches, and centimeters, allowing you to work directly with historical deed descriptions without manual conversion.
How to Use the Acreage Calculator
Choose Your Shape
Click the shape tabs at the top — Rectangle, Triangle, Circle, Trapezoid, Ellipse, Parallelogram, or Polygon. The input fields will update to match the selected shape. For most residential lots, Rectangle is the correct choice. For irregular parcels with many corners, choose Polygon and enter each vertex coordinate.
Enter Dimensions and Select Units
Type your measurements into the input fields and select the correct unit from the dropdown: feet, yards, inches, meters, centimeters, chains, or rods. You can use surveyor units (chains, rods) directly from an old deed description without converting manually. The calculator handles all conversions internally.
Read the Results
The primary result card shows the area in acres. Below it, the full conversion table gives square feet, square yards, square meters, hectares, square miles, and square kilometers. If your shape has a defined perimeter (rectangle or circle), the fencing cost estimator shows estimated costs for five common fencing materials.
Use Advanced Features
Enter an optional price per acre, per square foot, per square meter, or per hectare to calculate total land cost. Use the Subdivide field to split your parcel into equal lots and see each lot's dimensions. Enable Compare mode to measure a second plot side-by-side. Export to CSV or copy results to the clipboard for use in a spreadsheet or email.
Frequently Asked Questions
How many square feet are in an acre?
One acre equals exactly 43,560 square feet. This number comes from the historical definition: 1 chain (66 feet) multiplied by 1 furlong (660 feet) equals 43,560 square feet. So to convert a rectangular parcel to acres, multiply its length in feet by its width in feet, then divide by 43,560. For example, a 200-foot by 218-foot lot has 43,600 square feet, which is just slightly over 1 acre. The calculator does this math automatically for any shape you select.
How do I calculate acreage for an irregular-shaped lot?
For a lot with multiple corners, use the Polygon mode. Walk the boundary of your property with a measuring tape or obtain a survey plat, then record the (x, y) coordinates of each corner in a consistent unit such as feet. Enter each coordinate pair as a vertex. The calculator applies the shoelace formula — also known as the Gauss area formula — which computes the exact area of any closed polygon given its vertex coordinates. You need at least three vertices, and they should be entered in order (either clockwise or counterclockwise) around the boundary.
What is a chain, and why does it matter for land measurement?
A Gunter's chain is an old surveying unit equal to 66 feet, divided into 100 links of 0.66 feet each. It was the standard field measurement tool in American and British land surveys through the 19th century and into the 20th. Because 10 square chains equal exactly 1 acre, chain-based measurements made acreage arithmetic very simple for surveyors. Many older property deeds and government land grants in the US Public Land Survey System describe lots in chains and rods (1 rod = 16.5 feet = 0.25 chain). Our calculator accepts chains and rods as input units so you can work directly from historical deed descriptions.
What is the difference between an acre and a hectare?
An acre is 43,560 square feet (approximately 4,047 square meters), while a hectare is exactly 10,000 square meters (approximately 107,639 square feet). One hectare equals approximately 2.471 acres; conversely, 1 acre equals approximately 0.4047 hectares. The acre is the standard in the United States, Canada, and the United Kingdom for land measurement. The hectare is the standard in most other countries and is the official unit of the International System of Units (SI) for area. For agricultural purposes internationally, the hectare is more commonly reported, while US real estate almost always uses acres.
How much does it cost to fence an acre of land?
Fencing cost depends on the perimeter, which in turn depends on the shape of your parcel. A perfectly square 1-acre lot has sides of about 208.7 feet and a perimeter of about 835 feet. Fencing costs per linear foot vary significantly by material: split-rail runs about $10–$20, chain-link about $15–$25, wood privacy fence about $25–$35, vinyl fence about $30–$45, and wrought iron or aluminum about $35–$50 per linear foot. For a square 1-acre lot, total fencing costs would range from approximately $8,350 (split-rail) to $41,750 (wrought iron). Our calculator shows these ranges automatically when a perimeter can be calculated.
How do I convert square feet to acres for an oddly shaped lot?
Divide the total square footage by 43,560. For example, 21,780 square feet equals exactly 0.5 acres; 87,120 square feet equals 2 acres. For odd-shaped lots, the easiest approach is to divide the lot into simpler component shapes — rectangles, triangles — calculate each piece's square footage separately, add them together, and then divide by 43,560. Alternatively, use the Polygon mode in our calculator with the exact corner coordinates from your survey or plat map, and the shoelace formula will compute the total area directly.