Acreage Calculator
Calculate the acreage of any piece of land from measurements you take yourself — rectangular lots, triangles, trapezoids, circles, and irregular four-sided parcels. Results in acres, hectares, square feet, square meters, and perimeter. Free, private, runs 100% in your browser.
What this tool is (and isn’t)
- Is: a land-acreage calculator — it computes acreage from dimensions you measure (length × width, three sides, four sides + diagonal, radius…).
- Isn’t: an indoor square-footage tool — for rooms and floors use our Square Calculator.
- Isn’t: a pure unit converter — e.g. acres-to-hectares-converter only swaps between units; this tool calculates area from dimensions you measure.
- Isn’t: a map/GPS survey — it cannot look up your parcel; every number comes from dimensions you enter.
Calculate land acreage
How to measure a lot for acreage
Acreage formulas used
- Rectangle: area = length × width
- Triangle (base × height): area = ½ × base × height
- Triangle (3 sides): Heron’s formula — s = (a+b+c)/2, area = √(s(s−a)(s−b)(s−c))
- Trapezoid: area = (base A + base B) ÷ 2 × height
- Circle: area = π × radius²
- Irregular quadrilateral: area = Heron(a,b,diagonal) + Heron(c,d,diagonal)
Every result is then divided by the exact definition 1 acre = 43,560 sq ft (= 4,046.8564 m² = 0.404686 ha). Perimeter is the sum of the measured sides (or 2πr for circles). A triangle entered via base × height has no perimeter — switch to the 3-sides method if you need it.
Common lot sizes in acres
| Lot dimensions | Square feet | Acres |
|---|---|---|
| 50 × 100 ft | 5,000 | 0.1148 |
| 50 × 120 ft | 6,000 | 0.1377 |
| 60 × 120 ft | 7,200 | 0.1653 |
| 100 × 100 ft | 10,000 | 0.2296 |
| 150 × 150 ft | 22,500 | 0.5165 |
| 200 × 200 ft | 40,000 | 0.9183 |
| 208.71 × 208.71 ft | 43,559.86 | 1.0000 |
| 100 × 435.6 ft | 43,560 | 1.0000 |
Reference only — quarter acre = 10,890 sq ft, half acre = 21,780 sq ft. Your exact lot: enter its dimensions above.
Frequently asked questions
How many square feet are in an acre?
One acre is exactly 43,560 square feet, by definition. That is also 4,046.86 square meters or 0.4047 hectares. To convert any square footage to acres, divide by 43,560 — for example, 10,000 sq ft ÷ 43,560 = 0.2296 acres.
How do I calculate the acreage of a rectangular lot?
Multiply length × width in feet to get square feet, then divide by 43,560. Example: a 100 ft × 50 ft lot = 5,000 sq ft ÷ 43,560 = 0.1148 acres (464.52 sq m). Enter the dimensions above — the calculator does the division for you.
How big is an acre in feet? What does one acre look like?
A square acre measures about 208.71 ft on each side — more precisely 208.7103 ft, since the square root of 43,560 is 208.7103. (208.71² = 43,559.86 sq ft, which rounds to 1.0000 acre.) For scale: a FIFA soccer field (105 m × 68 m) is 1.7643 acres, so one acre is a little more than half a soccer field.
How do you calculate the acreage of an irregular or odd-shaped lot?
Measure the four sides plus one diagonal across the lot, then treat it as two triangles and apply Heron's formula to each — the diagonal splits the quadrilateral into two triangles whose areas add up. This calculator's Irregular mode does exactly that. Example: sides 120, 90, 120, 90 ft with a 150 ft diagonal = 10,800.00 sq ft = 0.2479 acres.
How do I find the area of a triangular lot?
If you know the base and height: area = ½ × base × height. Example: 10 ft × 6 ft ÷ 2 = 30 sq ft = 0.0007 acres. If you measured all three sides instead, use Heron's formula — a 3-4-5 ft triangle has area 6 sq ft = 0.0001 acres. Both methods are built into the Triangle mode above.
How many acres is a 50 × 120 ft lot?
50 × 120 = 6,000 sq ft. 6,000 ÷ 43,560 = 0.1377 acres — about one-seventh of an acre. Its perimeter is 340 ft.
How do you calculate the acreage of a circular area?
Area = π × radius², then divide by 43,560. A circle with a 100 ft radius = 31,415.93 sq ft = 0.7212 acres, with a circumference of 628.32 ft.
How do I convert acres to hectares?
Multiply acres by 0.4047 (1 acre = 4,046.86 m² = 0.4047 ha). Example: 2.5 acres × 0.4047 = 1.0117 hectares. The results above always show acres and hectares side by side, so no separate conversion step is needed. Note: a pure acres-to-hectares unit converter only converts between units — this tool computes acreage from measured dimensions.
Can I enter feet and inches?
Yes — choose the Feet + inches unit and enter each dimension as feet and inches. Example: 10 ft 6 in × 4 ft 0 in = 10.5 × 4 = 42 sq ft = 0.0010 acres.
How many acres is a soccer field?
A FIFA-regulation field (105 m × 68 m) covers 7,140.00 m² = 76,854.32 sq ft = 1.7643 acres (0.7140 hectares). An American football field including end zones (360 ft × 160 ft) is 57,600 sq ft = 1.3223 acres.
Why do two acreage calculators give slightly different results?
Usually rounding: 208.71 ft is a rounded one-acre side (the exact value is 208.7103 ft), and rounding inputs before multiplying compounds the error. For irregular lots, where you place the diagonal changes the two triangles slightly. GPS-based apps add satellite error on top. Measure in feet, keep full precision until the final step, and results here match the exact 43,560 sq ft definition.
What is the difference between this tool and a square footage calculator?
This tool computes land acreage from measured dimensions — including irregular lots via the diagonal method — and reports acres, hectares, square feet, square meters, and perimeter. For indoor square footage of rooms and floors, use our Square Calculator. A pure unit converter only converts between units; it cannot compute area from dimensions.
Free tool by NRTechStudio