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How to measure land area on a map with your iPhone

A rough fertiliser quantity for a field does not require walking the boundary with a tape. Open the Map tab, switch to Satellite, turn on the ruler (Measure distance and area) and tap the corners in order. Three points on and you get the enclosed area in m² or hectares, plus the path length through them.

2 min read · Updated 2026-09-16

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When a quick map measurement is enough

Seed or fertiliser for a field, the size of a garden, a roof outline for a quote, checking a listing's plot size before you drive out — none of these need survey-grade precision, just a number in the right ballpark. A satellite map and a few taps get you there.

Apple Maps itself has no area tool. That gap is the whole reason this guide exists. GeoProof's ruler sits on top of Apple's map and is part of the free version.

Steps: measure area on the map

  1. Open the Map tab and choose Satellite or Hybrid at the top so you can see the edges.
  2. Zoom in until the boundary fills the screen. The closer you zoom, the closer your taps land to the real corner.
  3. Tap the ruler button (Measure distance and area).
  4. Tap each corner of the plot in order, going round the shape.
  5. Read the distance through your points and, from the third point on, the area.
  6. Tap the reset arrow to start again. Turning the ruler off clears it.

Worked example

These two rectangles near San Francisco Bay were tapped out using the app's own formula — these are the numbers it gave back, not rounded for the page.

Area from four tapped corners
Corners (lat, long)App shows
37.798300, -122.377800 / 37.798300, -122.376800 / 37.797500, -122.376800 / 37.797500, -122.3778007834 m²
37.798300, -122.377800 / 37.798300, -122.374800 / 37.796500, -122.374800 / 37.796500, -122.3778005.29 ha

Below 10,000 m² the app shows square metres with no decimals; from 10,000 m² (1 hectare) up it switches to hectares with two decimals.

How the numbers are worked out

The distance adds up the ground distance between each tapped point and the next. It is an open path: the last point is not joined back to the first, so for a perimeter tap the first corner again at the end.

The area treats the points as a polygon on a flat projection centred on their average latitude. That is accurate enough for plots and fields, not for large regions or survey-grade work.

Tips and common mistakes

  • Tap corners in order around the shape — jump across it and you get a crossed polygon and a wrong area.
  • Satellite imagery can sit a few metres off true, and trees hide fence lines. Tap where the boundary actually is, not the shadow it casts.
  • Nothing is saved once you turn the ruler off. Screenshot it or write the figure into a project note if you will need it again.
  • The map itself needs internet. Pro users can cache OpenStreetMap tiles ahead of time in Settings > Offline Maps, but the ruler still lives on the Map tab.

Questions and answers

Can GeoProof show acres?
No. It shows m² and hectares only. One hectare is about 2.47 acres.
Is the area tool free?
Yes. The Map tab ruler is included in the free version.
Can I walk the boundary with GPS instead of tapping?
Pro can record a GPS track while you walk, with distance and time, but the area is measured only from points tapped on the map.
Why doesn't the distance match the perimeter?
The distance is an open path and does not close back to the first point. Tap the first corner again to include the last side.

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