Acreage CalculatorLot size to acres from feet, yards, meters, rods or chains
Measure any parcel — rectangular, triangular, round, trapezoid or an irregular four-sided lot — and get its acreage, a to-scale drawing beside a true one-acre square, every common area unit, and price per acre.
By Manzoor Ahmad · 13+ years of web development & SEO experienceLast updated: October 19, 2026
Your lot size
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Your lot, drawn to scale
The dashed square is exactly one acre (208.71 ft × 208.71 ft) at the same scale as your lot.
Area in every unit
How big is that, really?
How do you calculate acreage? Find the area of the land in square feet, then divide by 43,560 — the number of square feet in one acre. A rectangular lot 150 ft by 290 ft is 43,500 sq ft, and 43,500 ÷ 43,560 = 0.999 acres. For meters, divide square meters by 4,046.86; one hectare equals about 2.471 acres.
How to Use the Acreage Calculator
- Pick the shape closest to your lotRectangle for most subdivision lots; trapezoid when the front and back widths differ; irregular for any four-sided parcel with no right angles.
- Choose your unitUse feet for plats and listings, meters for international parcels, and rods or chains when you’re reading an older deed or survey.
- Enter the measurementsFor an irregular lot, add one diagonal (corner A to corner C). It splits the lot into two triangles so the area is exact rather than estimated.
- Read the drawing and add a priceCheck the to-scale drawing looks like your lot, then add an asking price to see cost per acre and per square foot.
Acreage Formulas for Every Lot Shape
Every acreage calculation is the same two steps: work out the area in square feet, then divide by 43,560. Only the area formula changes with the shape.
Rectangle: Acres = length × width ÷ 43,560
Triangle (three sides, Heron’s formula): s = (a + b + c) ÷ 2; area = √[s(s − a)(s − b)(s − c)]
Circle: Area = π × radius²
Trapezoid: Area = (front + back) ÷ 2 × depth
Irregular four-sided lot: Area = triangle(AB, BC, AC) + triangle(AC, CD, DA)
Worked example: irregular lot
Sides AB 180 ft, BC 240 ft, CD 200 ft, DA 220 ft, diagonal AC 300 ft.
- Triangle ABC: s = 360 → area ≈ 21,600 sq ft
- Triangle ACD: s = 360 → area ≈ 21,996 sq ft
- Total ≈ 43,596 sq ft ÷ 43,560 = 1.001 acres
Why “average the sides” is wrong
A shortcut you’ll see online multiplies the average of opposite sides: ((180 + 200) ÷ 2) × ((240 + 220) ÷ 2) = 43,700 sq ft. That’s close here, but the error grows fast as corners move away from 90°. On a lot shaped like a slanted parallelogram the shortcut can overstate the area by 20% or more — which is why surveyors and this calculator use a diagonal instead.
Acre Conversion Factors
These are the exact relationships behind every result above. Since January 1, 2023, U.S. land measurements are defined using the international foot (exactly 0.3048 m) after the National Institute of Standards and Technology retired the old U.S. survey foot — the difference is only about two parts per million, but it means one acre is now exactly 4,046.8564224 square meters.
| 1 acre equals | Value | Useful when |
|---|---|---|
| Square feet | 43,560 | Reading U.S. plats, listings and tax records |
| Square yards | 4,840 | Sod, seed and landscaping quotes |
| Square meters | 4,046.86 | International and metric surveys |
| Hectares | 0.404686 (1 ha = 2.47105 acres) | Farmland in Canada, the UK, Australia and Europe |
| Square miles | 1/640 (0.0015625) | Sections and large ranch parcels (1 section = 640 acres) |
| Square chains / rods | 10 sq chains / 160 sq rods | Older deeds and metes-and-bounds descriptions |
| Square side | 208.71 ft × 208.71 ft | Picturing an acre on the ground |
Where the acre came from: historically an acre was the land a team of oxen could plow in a day, standardized as one furlong (660 ft) by one chain (66 ft). 660 × 66 = 43,560 — which is why the number looks so odd today. A 660 ft × 66 ft strip is still exactly one acre.
Common Lot Sizes in Acres and Square Feet
Listings often describe lots as fractions of an acre. Here’s what those fractions mean in square feet, square meters, and the side length of a perfectly square lot of that size.
| Acres | Square feet | Square meters | Square lot side |
|---|---|---|---|
| 1/8 acre | 5,445 | 506 | 73.8 ft |
| 1/4 acre | 10,890 | 1,012 | 104.4 ft |
| 1/3 acre | 14,520 | 1,349 | 120.5 ft |
| 1/2 acre | 21,780 | 2,023 | 147.6 ft |
| 3/4 acre | 32,670 | 3,035 | 180.7 ft |
| 1 acre | 43,560 | 4,047 | 208.7 ft |
| 2 acres | 87,120 | 8,094 | 295.2 ft |
| 5 acres | 217,800 | 20,234 | 466.7 ft |
| 10 acres | 435,600 | 40,469 | 660.0 ft |
| 40 acres | 1,742,400 | 161,874 | 1,320 ft (¼ mile) |
Lot Dimensions to Acres
Typical rectangular lot dimensions in feet, converted to square footage and acreage. Use it as a quick sanity check before you list or buy.
| Lot dimensions | Square feet | Acres |
|---|---|---|
| 50 × 100 ft | 5,000 | 0.115 |
| 60 × 120 ft | 7,200 | 0.165 |
| 75 × 150 ft | 11,250 | 0.258 |
| 100 × 100 ft | 10,000 | 0.230 |
| 100 × 150 ft | 15,000 | 0.344 |
| 100 × 200 ft | 20,000 | 0.459 |
| 200 × 200 ft | 40,000 | 0.918 |
| 150 × 300 ft | 45,000 | 1.033 |
| 330 × 660 ft | 217,800 | 5.000 |
| 660 × 660 ft | 435,600 | 10.000 |
Why Your Acreage Might Not Match the Listing
Buyers are often surprised when their own measurement, the listing and the tax record give three different numbers. These are the usual reasons — and which number to trust.
Common causes of differences
- Gross vs. net acreage. Some records include land to the road centerline or under easements; others exclude it.
- Slope. Legal area is measured horizontally. Pacing or taping along a hillside overstates the area.
- Rounded assessor data. Tax records are often rounded or based on older maps and GIS estimates.
- Irregular corners. Treating a skewed lot as a rectangle can be off by thousands of square feet.
Which number to trust
- A recorded boundary survey is the most reliable figure for buying, building or splitting land.
- The plat or deed gives dimensions you can enter here to check the stated acreage.
- County GIS parcel maps are good for estimates, not legal boundaries.
- Your own tape measurements work for budgeting fence, seed or sod — not for legal purposes.
Related Land and Property Calculators
Once you know the acreage, these tools help you plan what goes on the land and what it will cost.
Acreage Calculator FAQs
One acre is exactly 43,560 square feet. That equals 4,840 square yards or about 4,046.86 square meters.
Multiply the lot’s length by its width in feet to get square feet, then divide by 43,560. For non-rectangular lots, use the matching shape formula or the irregular-lot option with a diagonal, which this calculator does for you.
An acre has no fixed shape, but a square acre measures about 208.71 feet on each side. A rectangle of 66 by 660 feet, or 100 by 435.6 feet, is also exactly one acre.
Measure all four sides plus one diagonal between opposite corners. The diagonal splits the lot into two triangles; find each triangle’s area with Heron’s formula from its three sides, add them, and divide by 43,560. Lots with more than four sides can be split into more triangles the same way.
A quarter acre is 10,890 square feet — roughly 104 feet square, or about 75 by 145 feet. It comfortably fits a single-family home with a yard and is a common suburban lot size.
An American football field including both end zones is 360 by 160 feet, or 57,600 square feet — about 1.32 acres. Without end zones it is 300 by 160 feet, about 1.10 acres.
Multiply hectares by 2.47105. To go from acres to hectares, multiply acres by 0.404686. Use the Convert an area mode to convert between any of seven units at once.
A surveyor’s chain is 66 feet and a rod (also called a pole or perch) is 16.5 feet. Ten square chains or 160 square rods make one acre. Choose chains or rods as the unit and enter the deed’s measurements directly.
Divide the total price by the number of acres. A $85,000 lot of 2.5 acres costs $34,000 per acre. Enter an asking price in the calculator to see price per acre and per square foot automatically.
Assessor records may round acreage, include land to the road centerline, rely on older maps, or measure differently from a modern survey. A recorded boundary survey is the authoritative source for legal acreage.
Legal acreage is a horizontal measurement, so a sloped lot has the same acreage as a flat lot with the same horizontal footprint. Measuring along the ground on a hillside will overstate the area; surveyors correct for this.
Yes. It is free, needs no sign-up and runs entirely in your browser — your measurements and prices are not sent to DexoCalc or stored.
Manzoor Ahmad
13+ years of web development & SEO experience · Founder, DexoCalc
Manzoor builds and maintains every DexoCalc calculator. This tool uses the exact unit definitions published by NIST, computes irregular lots by triangulation the way surveyors do, and draws each lot to scale so you can spot a mistyped measurement before relying on the number.
Sources
Results are estimates based on the measurements you enter and are not a land survey. For purchases, boundary disputes, subdivisions or permits, rely on a survey by a licensed land surveyor.