Lawn Size Calculator: Square Feet and Acres of Your Yard

Break the lawn into simple shapes, measure each one and add them up. A 100 foot tape or a measuring wheel is the easiest tool; pacing works for a rough estimate if you first measure your own stride over 50 feet. Work in feet and round to the nearest foot, which is accurate enough for buying seed, fertilizer or a mower.

1. Sketch the yard and divide the grass into rectangles, triangles and circles.
2. Measure each shape and calculate its area with the formulas below.
3. Add the lawn shapes together.
4. Subtract anything inside those shapes that is not grass: the house footprint, driveway, patio, pool deck, sheds and planting beds.
5. Divide the total by 43,560 to convert square feet to acres.

One acre is 43,560 square feet. The mower column assumes the whole area is open lawn; use your measured grass area for a real recommendation.

Yes, and it is often faster than a tape for large or irregular yards. Most free online map services have a measure distance or measure area tool in satellite view: right-click a starting point, choose the measure option, then click around the edge of each lawn section to trace it. Some county property appraiser sites also show parcel dimensions. Satellite tracing is usually accurate to within a few percent, but trees hide lawn edges, so walk the yard to check beds and shaded corners before you buy seed or fertilizer by the bag. Enter the traced areas in the calculator as rectangles with a width of 1 and a length equal to the square footage if the tool gives you area directly.

Mowing time scales directly with area and inversely with deck width. A 21 inch walk-behind covers about 0.43 acres an hour, so a half acre of lawn is more than an hour of walking every week of the season. A 42 inch zero-turn covers about 1.9 acres an hour. For under about a third of an acre, a battery walk-behind such as the EGO POWER+ LM2135SP 21 in. Select Cut Self-Propelled Mower Kit is the sensible buy. From half an acre to 1.5 acres a 42 inch rider such as the Husqvarna TS 120 42 in. Lawn Tractor or the battery EGO POWER+ Z6 ZT4204L 42 in. Electric Zero Turn Mower saves hours each month, and past 2 acres a 48 to 54 inch zero-turn like the Husqvarna Z254F 54 in. Zero Turn Mower is the standard choice. Robot mowers are rated by area: check that your lawn is under about 80 percent of the rating, as with the Husqvarna Automower 430X Robot Mower rated for 0.8 acres. See the best mowers for 1 acre and robot mower size by lawn area.

Seed and fertilizer are sold by coverage, so the square footage converts straight to bags. Tall fescue is seeded at about 6 to 8 pounds per 1,000 square feet for a new lawn and roughly half that for overseeding, so a 5,000 square foot lawn needs about 35 pounds for bare soil. A fertilizer with 32 percent nitrogen takes about 3.1 pounds of product to apply 1 pound of nitrogen per 1,000 square feet, so the same lawn uses about 16 pounds per application. Always follow the rate on the product label. Exact amounts by grass type are in the grass seed calculator and the fertilizer calculator.