At Ben's Place

Calculators Lawn area

How big is my lawn?

Almost no lawn is a neat rectangle. Break yours into pieces that are, add a zone for each, and this adds them up. Every fertiliser, wetter and herbicide rate you will ever read depends on getting this roughly right.

Total area
Add a zone

You do not need to be exact. Within about five percent is plenty, because the rates on the bag are a range anyway. What you want to avoid is guessing 200m² when it is really 110m², which is the difference between feeding right and feeding double.

Fastest way: Google Maps satellite view, right click a corner, measure distance, click round the perimeter. Good enough for a suburban block and it beats a tape on a hot day.

The longer version

Breaking it into zones

  • Split at the obvious lines. A path, a driveway edge or a garden bed usually cuts a lawn into two or three near-rectangles.
  • Curved edge? Treat it as a rectangle to the middle of the curve. What you lose one side you gain the other.
  • Pace it out if you have no tape. A comfortable adult stride is close to a metre, and you can check yourself against a car or a fence panel.
  • Only subtract things sitting in the lawn if they are more than a few square metres.

The app does this and keeps score

This adds up your zones once. The lawn app holds your lawn's details so you never re-enter them, and it tracks the nitrogen you have already put down this year so later doses shrink instead of pushing you over the cap. Free, no account, works offline.