GardenCalcs.uk
Lawn Area Calculator — Measure Your Lawn
Calculate your lawn area including irregular shapes and obstacles.
Pick the outline that best matches your lawn; split a complex lawn into separate shapes and add the results.
Longest side of the lawn in metres.
Shorter side of the lawn, measured at right angles to the Length, in metres.
Total m² of beds, paths, ponds, trees and sheds inside the lawn to subtract from the gross area.
How We Calculate This
Rectangle: Length × Width, perimeter 2 × (L + W). Circle: π × (Diameter/2)², circumference π × Diameter. Triangle: ½ × Base × Height (the perimeter assumes a right-angled triangle whose Length and Height are the two perpendicular sides).
L-shape: the bounding rectangle minus the missing corner — Area = (L × W) − (notch L × notch W). Its perimeter equals the bounding rectangle, 2 × (L + W).
Obstacle areas (flower beds, paths, sheds) are subtracted from the gross area to give the net lawn area. The perimeter is also reported for edging requirements.
Frequently Asked Questions
Break it into simple shapes (rectangles, triangles, circles). Calculate each section separately and add them together. Subtract any obstacles like paths or flower beds.
Lawn area is essential for calculating correct quantities of seed, feed, weedkiller, and top dressing. Too much or too little of any product causes problems.
For a roughly circular lawn, measure the diameter (longest width). For a kidney shape, calculate as a circle minus cut-out areas.
Use Google Maps satellite view. Zoom in, use the measure distance tool to trace the perimeter, and it will calculate the area. This gives a rough but useful estimate.
Yes. Subtract the area of any beds, ponds, trees, or paths within the lawn to avoid over-ordering materials like seed, feed, or turf.
An L-shape is the overall (bounding) rectangle with one rectangular corner cut away. Enter the full Length and Width of the bounding rectangle, then the Length and Width of the missing corner. Area = (L × W) − (notch L × notch W). The perimeter of an L-shape is the same as its bounding rectangle, 2 × (L + W), because the two inner notch edges exactly replace the outer edges they cut into.
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Last updated: February 2026
All calculations are estimates based on standard gardening guidelines. Results may vary with soil conditions, climate, and plant varieties.