Land Area Calculator
Click the corners of a lot, field or yard on the map, or paste GPS coordinates, to measure its area in acres, square feet and hectares plus the perimeter and the length and bearing of every side. Measurements are computed on the WGS84 Earth model right in your browser.
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Click each corner of the lot in order. Drag a corner to move it, drag a small middle dot to add a corner, double-click a corner to delete it.
Decimal degrees (41.90123, -93.50123) or degrees-minutes-seconds (41°54'04.4"N 93°30'04.4"W). At least 3 points, in order around the boundary. The shape closes automatically.
| Square feet | – |
|---|---|
| Square yards | – |
| Square meters | – |
| Hectares | – |
| Square miles | – |
| Square km | – |
| Perimeter | – |
| Corners | 0 |
Boundary sides
| Side | Start corner (lat, lon) | Length (ft) | Length (m) | Bearing |
|---|
How to use the Land Area Calculator
- Find the property: search a town or address, or type coordinates like 41.90, -93.50, then zoom in with the wheel or the + button.
- Click each corner of the lot in order around the edge. The area appears as soon as there are 3 corners and updates with every click.
- Fine-tune the shape: switch to Satellite to see fences and field edges, drag corners into place, drag a middle dot to add a corner on a curve, double-click a corner to remove it.
- Or enter GPS points: open the Enter GPS points tab, paste one latitude, longitude pair per line and press Calculate area.
- Read and save the results: acres, square feet, hectares and perimeter are on the right and every side is listed below the map. Copy the results or download GeoJSON, KML or CSV.
How the land area is calculated
Each corner is a latitude and longitude on the WGS84 ellipsoid, the same Earth model GPS uses. To get the area, the boundary is projected with an equal-area projection (the ellipsoidal sinusoidal projection) centered on your shape, and the projected polygon is measured with the shoelace formula:
Area = ½ × |Σ (xi × yi+1 − xi+1 × yi)|
Because the projection preserves area, this gives the true surface area instead of the inflated area you would get by measuring pixels on a web map, where a shape near 45° latitude looks about twice its real size. Side lengths and bearings use Vincenty's inverse formula on the same ellipsoid, and the perimeter is the sum of the sides. Results are then converted with exact definitions: 1 acre = 43,560 ft² = 4,046.8564224 m², 1 hectare = 10,000 m².
Lot and field sizes for reference
| Area | Square feet | Square meters | Square side length | Typical example |
|---|---|---|---|---|
| 1/8 acre | 5,445 | 506 | 73.8 ft | Small city lot |
| 1/4 acre | 10,890 | 1,012 | 104.4 ft | Suburban house lot |
| 1/2 acre | 21,780 | 2,023 | 147.6 ft | Large suburban lot |
| 1 acre | 43,560 | 4,047 | 208.7 ft | About 75% of an American football field with end zones (57,600 ft²) |
| 1 hectare (2.47 acres) | 107,639 | 10,000 | 328.1 ft (100 m) | Common metric field size |
| 5 acres | 217,800 | 20,234 | 466.7 ft | Hobby farm or homestead |
| 40 acres | 1,742,400 | 161,874 | 1,320 ft (1/4 mile) | Quarter-quarter section (US public land survey) |
| 160 acres | 6,969,600 | 647,497 | 2,640 ft (1/2 mile) | Quarter section |
| 640 acres | 27,878,400 | 2,589,988 | 5,280 ft (1 mile) | Section (1 square mile) |
Tips for an accurate measurement
- Zoom in close before placing corners. At zoom 18 to 19 one screen pixel is well under a meter, so your clicks are far more precise than at town level.
- Use Satellite view to follow fence lines, hedges, field edges and driveways, then switch back to Map to check street names.
- Add corners along curves: drag the small middle dot on a curved edge (a creek, cul-de-sac or round pond) to bend the boundary. More corners mean a better fit.
- Walking the boundary with GPS? Stand still at each corner for a few seconds in the open before pressing Add my GPS position. Trees and buildings reduce phone accuracy.
- Pasting deed coordinates: keep the points in order around the parcel. If the warning about a crossing boundary appears, two points are out of order.
- Remember the limits: imagery can be shifted a few meters from true position, which matters most on small lots. For legal acreage use the recorded survey.
Frequently asked questions
How do I find out how many acres my lot is?
Search your address, switch to Satellite, zoom in until you can see the property lines, fences or field edges, and click each corner in order. The calculator shows the area in acres right away. One acre is 43,560 square feet, so you can also divide a known square footage by 43,560.
How accurate is measuring land area on a map?
The math is accurate to well under 0.1% for lots and fields, because the area is computed on the WGS84 ellipsoid. The real limit is how precisely you place the corners: map and satellite imagery can be offset by a few meters and a phone GPS fix under open sky is typically within about 5 meters. A small residential lot can therefore be off by a few percent; larger fields are proportionally more accurate.
Can I use this instead of a land survey?
No. It is great for estimating acreage, planning fencing, seeding or mowing and checking a listing, but property boundaries are legal descriptions. For a sale, a boundary dispute or a building permit, rely on the recorded plat or deed and a licensed land surveyor.
What coordinate formats can I paste?
One point per line in decimal degrees such as 41.90123, -93.50123, or degrees-minutes-seconds such as 41°54'04.4"N 93°30'04.4"W. Latitude comes first. Use negative numbers or S and W for the southern and western hemispheres. If your file lists longitude first, press Swap lat/lon.
How many square feet are in an acre and a hectare?
One acre is 43,560 square feet, 4,840 square yards or about 4,046.86 square meters. One hectare is 10,000 square meters, about 107,639 square feet or 2.471 acres. One square mile is 640 acres.
What does the bearing in the sides table mean?
It is the direction from one corner to the next, shown the way surveyors write it (for example N 45°30' E means 45.5 degrees east of north) and as an azimuth from 0 to 360 degrees clockwise from true north. Bearings in an old deed may be referenced to magnetic north or a different datum, so small differences are normal.
Can I open the shape in Google Earth or GIS software?
Yes. Download KML to open it in Google Earth, or GeoJSON for QGIS, ArcGIS and most web maps. The CSV lists every corner with its coordinates, the length of the side to the next corner and the totals.
Are all the tools on FreeToolCabin tested for quality and accuracy?
Yes! Every tool on our site undergoes automated Q/A testing in real browser environments to ensure high precision, correct output, and zero errors. If you happen to spot a bug or have a suggestion, please contact us at [email protected] and our team will review it right away.