How to measure your lawn

By the Gladeburn team

Sources awaiting check

Lawn area calculator

Worked example

For a 12 m × 9 m back lawn with a 2 m round bed, and an 8 m × 6 m L-shaped front lawn with a 3 m × 2 m corner cut out:

  • Back lawn: 104.86 m² (108 m² less 3.14 m² of bed).
  • Front lawn: 42 m².
  • Total: 146.86 m² (1,581 ft²) across 2 zones.

You don't need a surveyor or an app. A long tape measure, a notepad and ten minutes will give you a figure good enough to choose a robot mower.

The short answer

Split the lawn into simple shapes, measure each one, add them up, then take away beds, patios and ponds. Measure each separate lawn as its own zone. The calculator above does the sums in m² and ft².

A worked example

A 12 m × 9 m back lawn is 108 m². It has a round bed 2 m across in the middle, which is about 3.1 m², so the mowable back lawn is about 104.9 m². The front lawn is an L-shape: an 8 m × 6 m rectangle with a 3 m × 2 m corner taken out by the drive, so 48 − 6 = 42 m². Together, that's about 146.9 m² in two zones.

What you'll need

Step by step

  1. Sketch the lawn roughly from above, and mark anything the mower won't cut: beds, patios, ponds, sheds.
  2. Break it into shapes. Rectangles are easiest. Use triangles for angled bits and circles for round beds.
  3. Measure each shape. For a triangle, measure all three sides: no right angle needed.
  4. Measure separate lawns separately. They become zones in the calculator, and some mowers need each one set up on its own.
  5. Note your narrowest passage between lawns while you're out there: the chooser asks for it.

Irregular lawns

For a curvy lawn, pick a fixed starting point, such as a corner of the house. Walk round the edge and, at each bend, note how far across and how far along it is from that point. Enter the pairs in the calculator's "points" shape and it joins them up.

FAQs

Should I measure in metres or feet?

Either: the calculator takes both. Robot mower specs are in m², so that's what it shows first.

Does the lawn area include paths?

Include grass paths the mower will cross. Leave out paving and gravel.

How accurate does it need to be?

Within about a tenth is fine for choosing a mower, because you'll add headroom above it anyway.

Sources