Lawn Square Footage Calculator, Any Shape of Yard
The number you need is the grass, not the plot. This lawn size calculator lets you add up as many pieces of lawn as your yard actually has, then take off the drive, the beds and the house. Every seed bag, fertilizer rate and mowing quote depends on getting that one square footage right.
Your lawn area
| Unit | Your lawn |
|---|---|
| Square feet | 1,920 |
| Square yards | 213 |
| Square meters | 178 |
| Acres | 0.044 |
| Hectares | 0.018 |
Your measurement
1,920 sq ft of lawn (0.044 acres)
2,400 sq ft of grass measured, less 480 sq ft that is not grass. Keep this figure: every other lawn calculation on the site starts from it.
- What comes off the lot
- 20% of what you measured was excluded. A typical suburban plot loses 40% to the house, drive and beds, so if your figure is far from that it is worth a second look.
- How this is worked out
- + Front lawn: 2,400 sq ft− Driveway: 480 sq ft= 1,920 sq ft of lawn
What is lawn area?
Lawn area is the grass you actually cut, not the size of your plot. Those two are rarely close. Take the lot, then subtract the house footprint, the driveway, the patio, the beds and anything else that isn't grass. On a new build with a small plot, half the lot can disappear that way.
Almost every other number for your lawn starts here. Seed, fertilizer, mowing time, what a contractor should charge. They're all rates per thousand square feet or per acre, so they all inherit whatever error is in this one figure.
And that error costs money every time. Buy seed for a quarter-acre plot when the grass is really 6,534 sq ft and you've paid for 40% more than you need. Spread fertilizer at that rate and you'll burn the lawn rather than feed it.
How to calculate lawn size
Split the lawn into shapes, measure each one, add the grass and subtract everything else. That’s the whole method, and doing it in pieces is both easier and more accurate than trying to force an odd-shaped yard into a single rectangle.
| Shape | Measure | Formula |
|---|---|---|
| Rectangle | Length and width | length × width |
| Triangle | Base and height | base × height ÷ 2 |
| Circle | Diameter | π × (diameter ÷ 2)² |
| Curved strip | Length and average width | length × average width |
A 60 by 40 ft front lawn is 2,400 sq ft. Take off a 40 by 12 ft driveway at 480 sq ft and you’re left with 1,920 sq ft of grass. That subtraction is the step people skip, and it’s worth about a fifth of the answer on a typical front yard.
Work in feet throughout and convert at the end. Here's the error that catches most people: mixing feet and yards partway through. A square yard is nine square feet, not three. So the mistake is bigger than it looks.
Measuring an irregular yard
Almost no lawn is one clean shape. The trick is not to find a clever formula but to draw a rough plan and cut it into pieces you can measure with a tape.
Break it into blocks
Sketch the yard, then draw straight lines across it to make rectangles and triangles. Aim for four or five pieces rather than one approximation or fifteen tiny ones. Each piece needs two measurements, so a five-piece yard is ten numbers and about fifteen minutes of work.
Handle curves with average width
For a curved bed edge or a bowed boundary, measure the width at three or four points along the strip and use the middle value. The bulges and the pinches cancel, and the result is usually within a couple of percent of a proper calculation.
Pace it if you have no tape
Measure your own stride once against a known distance, then pace the yard. Most adults land between 2.5 and 3 ft a step. It sounds crude and it gets you inside 5%, which is well within the tolerance of everything you’ll use the figure for.
Lot size against actual grass
A deed or assessor record gives you the plot, and the plot is always bigger than the lawn. On a typical suburban property the house takes about 20%, the driveway and paths another 10%, and beds, patio and shed roughly 10%.
| Lot | Plot area | Grass at 60% | Acres of grass |
|---|---|---|---|
| City lot | 5,000 sq ft | 3,000 sq ft | 0.07 |
| Quarter acre | 10,890 sq ft | 6,534 sq ft | 0.15 |
| Third acre | 14,520 sq ft | 8,712 sq ft | 0.2 |
| Half acre | 21,780 sq ft | 13,068 sq ft | 0.3 |
| One acre | 43,560 sq ft | 26,136 sq ft | 0.6 |
That 40% is a rule of thumb and nothing more. A new build on a small plot can lose half the lot to the house and drive. An older property on an acre might only lose a tenth. Use the table to check whether your measurement is plausible, then trust the measurement.
The difference matters more than it sounds. Buying seed for a quarter-acre plot rather than its 6,534 sq ft of actual grass means paying for 40% more than you need, every time, and over-applying fertilizer at that rate will burn the lawn rather than feed it.
Lawn area in every unit
Square feet is the working unit for seed, fertilizer and sod in the US. Acres turn up on mowing rates and property records, square meters on anything imported, and square yards on some sod orders.
| Unit | 1,000 sq ft | 5,000 sq ft | One acre |
|---|---|---|---|
| Square feet | 1,000 | 5,000 | 43,560 |
| Square yards | 111 | 556 | 4,840 |
| Square meters | 93 | 465 | 4,047 |
| Acres | 0.023 | 0.115 | 1 |
| Hectares | 0.009 | 0.046 | 0.4 |
The two worth memorizing are 43,560 sq ft to the acre and 9 sq ft to the square yard. The second one catches people because three feet make a yard, so the instinct is to divide by three rather than nine.
Seed and fertilizer are almost always rated per 1,000 sq ft, which is why that column is first. So divide your lawn area by 1,000. That gives you the number of doses, which is far more useful than the raw area when you're stood in front of a shelf of bags.
What you need the figure for
Lawn area is the input to almost everything else. Getting it right once saves re-measuring every time you buy something or price a job.
| Job | Rated per | A 6,534 sq ft lawn |
|---|---|---|
| Grass seed, new lawn | 1,000 sq ft | 6.5 doses |
| Fertilizer | 1,000 sq ft | 6.5 doses |
| Mowing time, walk-behind | Acre | 37 min a visit |
| Sod | Piece or pallet | 6,991 sq ft with waste |
| Topsoil, 2 in topdressing | Cubic yard | 40.3 yd³ |
Sod is the one where accuracy pays. Sod is sold by the piece, delivered on a schedule, and has to go down within a day. Come up short and the job stops. Order too much and it dies in the driveway. Add 5 to 10% for cuts and awkward edges and no more.
Everything else has tolerance. Seed at 5% over is fine, mowing time barely notices, and fertilizer is the only place where too much does damage rather than just costing money. That’s the one to measure carefully and apply carefully.
Weed and feed products are stricter still, because the herbicide rate is set by law rather than by the manufacturer. Over-applying those is both a wasted bag and a label violation, so the area figure has to be honest even where nobody is checking.
Measuring from a satellite map
For a large or awkwardly shaped yard, an aerial view beats a tape. Most mapping tools have an area mode. You click round a boundary and it returns the enclosed area. That handles curves and odd angles without any arithmetic at all.
Two things to watch. The first is scale: check the reading against something you know the size of, usually your own house, before trusting a number. The second is that overhanging trees hide grass, so a boundary drawn from the image alone tends to come out small on a mature property.
It’s also worth remembering that aerial imagery can be several years old. Beds get dug. Sheds get built. Driveways get widened. So treat the outline as a starting point, then adjust for anything that's changed since the photograph.
Lawn measurement questions
How to calculate lawn size?
Break the grass into rectangles and triangles, with a circle where you need one, then work out each piece, then add them up and subtract anything that’s not grass. Length times width for a rectangle, half base times height for a triangle, and pi times the radius squared for a circle.
How to calculate square footage of a lawn?
Measure in feet and multiply. A 60 by 40 ft front lawn is 2,400 sq ft. Do each section separately. Don't try to treat an irregular yard as one shape. The error on a single rough rectangle is far bigger than the error on four accurate ones.
How do I calculate my lawn size without measuring?
Take the lot size from your deed or county assessor record and subtract about 40% for the house, the driveway and any beds. On a quarter-acre plot that leaves roughly 6,534 sq ft of grass. It’s a starting figure, not a measurement.
How many square feet are in an acre of lawn?
43,560 sq ft, which is about 4,047 square meters. A quarter acre is 10,890 sq ft and a half acre is 21,780, though the grass on those plots is always less once the buildings come off.
How do I measure an irregular lawn?
Split it into shapes you can measure and add them. For curved edges, treat the strip as a rectangle at its average width, measuring at several points and taking the middle. Small errors either side of a curve cancel out surprisingly well.
Should I include the driveway in my lawn area?
No. Every calculation that uses lawn area, from seed to mowing time to fertilizer, applies to grass only. Including hard surfaces means buying too much of everything and quoting jobs that take less time than you charged for.
How accurate does lawn measurement need to be?
Within about 5% is plenty. Seed and fertilizer rates have tolerance built in and mowing time barely moves. Where it matters more is sod, which is bought by the piece and cut to fit, so measure that job properly and add 5 to 10% for waste.
Can I measure my lawn from a satellite map?
Yes, and it beats a tape for a large or awkward yard. Most mapping tools have an area measurement mode where you click round a boundary. Check the scale against something you know, like your house, because the reading is only as good as the outline you drew.