Foot Acreage Calculator
Calculate land area from dimensions or draw a boundary on a map. See acres, square feet, hectares and perimeter.
Measure your land
Add separate spaces; do not overlap them. Use a subtracting area for an island or fixture. Changing units reinterprets the numbers; re-enter dimensions in the selected unit.
Your measurements stay in this browser and the share link. No sign-up needed.
At a glance
Enter your measurements, then calculate.
Keep full precision while calculating. Round only when planning or ordering.
See formulas & sources ↗A simple way to measure
- Sketch the space and divide it into shapes that do not overlap.
- Enter each shape’s dimensions. For feet and inches, enter 10 and 6 for a 10 ft 6 in measurement.
- Add closets or separate spaces as new areas. Mark an island or other exclusion as a subtraction.
- Check the net area before adding a material allowance. Waste increases the order quantity; it does not increase your measured floor or land area.
Example: two spaces and a cutout
A 12 × 10 ft space is 120 sq ft. Add a 4 × 6 ft space and subtract a 2 × 3 ft fixture: the net is 138 sq ft. With 10% extra, plan for 151.8 sq ft.
Choose the right dimensions
For a circle, measure the radius from the center to the edge, not the full diameter. A triangle needs a perpendicular height. A trapezoid needs two parallel sides and the perpendicular distance between them. For an L-shape, enter the full outer rectangle and the missing corner.
Drawing a land boundary
Choose “Draw on a map” and load OpenStreetMap. Move to coordinates near the property, zoom in and click each corner around the boundary in order. Use Undo if you misplace a point. Three or more points form a closed polygon; Calculate gives the area and the full boundary perimeter.
The result uses a spherical geodesic formula, not flat screen pixels. Street maps are not cadastral surveys: imagery, visible fences and clicks can all differ from legal boundaries. Slopes do not increase this horizontal area estimate. Use a licensed surveyor for boundary or transaction decisions.
You can paste longitude,latitude pairs without loading tiles. Coordinates, zoom and map center are included in a saved link. Drawings crossing the date line or above 85° latitude are not supported.
Formulas and exact conversion constants: methodology and sources.
Acreage questions
How many square feet are in an acre?
One acre is exactly 43,560 sq ft, about 208.71 ft on each side if it were a square.
How do I calculate acreage from feet?
Multiply length by width in feet, then divide by 43,560. A 200 × 150 ft lot is 30,000 sq ft, or 0.689 acres.
How big is a quarter acre?
10,890 sq ft. Half an acre is 21,780 sq ft.
How accurate is drawing on the map?
It depends on how closely you click the corners and how well the map imagery lines up. It is useful for planning and estimates, but it is not a survey. For legal boundaries, use your deed, plat or a licensed surveyor.
What is the difference between acres and hectares?
A hectare is 10,000 m², about 2.471 acres. One acre is about 0.4047 hectares.
How do I measure an irregular lot?
Draw the boundary on the map, enter the corner points, or split the lot into shapes and add them together.