Check Land Area Against Your Deed: Why the Numbers Differ

Published November 6, 2026

To check your land area against the deed, measure the plot yourself on a satellite map or by walking it with GPS, then compare. A gap of a few percent is normal and usually means nothing. To know whether yours is real, multiply the plot's perimeter by how far off your edges could be: if the difference is smaller than that, it's measurement noise, and if it's larger, something on the ground or in the records has changed.

Most people only find out the numbers disagree when they're about to buy, sell, fence or split land. This guide shows how to check in an afternoon and how to read the result.

Where the "official" number comes from

A plot can carry several areas, and they rarely match each other exactly:

• The deed. Often copied forward from an old survey, sometimes decades old, and often followed by "more or less". Older surveys used chains, compasses and paper maths.
• The tax or assessor record. County parcel maps and GIS viewers are drawn to help assess tax. They're approximate, and most say so in small print.
• A recorded plat or survey. Prepared by a licensed surveyor from measurements on the ground. This is the most reliable figure, but only for the land as it was on the day it was surveyed.
• In England and Wales, the title plan. HM Land Registry plans show general boundaries, not the exact line, so the area printed on a sales brochure may come from somewhere else entirely.

So before asking "is my deed wrong?", ask which record the number came from and how old it is.

How to check your land area yourself

1. Write down the official figure and its unit. Acres, hectares or square feet, and which document it came from.
2. Measure on the satellite map. Tap each corner of the plot. Zoom in close on each one so the point sits on the real fence, wall or boundary marker, not on a tree shadow. Measuring by satellite or GPS covers the technique.
3. Walk it if the edges are hard to see. Under trees, or where two fields look the same from above, walk the boundary with GPS instead. Measuring land by walking explains how to handle fences and ditches.
4. Note the perimeter as well as the area. You need it for the next step.
5. Run the error-band test below before you draw any conclusion.

The error-band test: is the difference real?

Every measurement has fuzzy edges. Under open sky a phone's GPS is typically accurate to about 3–5 m, and a corner tapped on a clear satellite image can still be off by a metre or two. The area you could gain or lose is roughly:

perimeter × how far off your edges could be

If the gap between your figure and the deed is smaller than that band, you can't tell the two apart. If it's clearly bigger, it's worth finding out why.

The lesson: on big fields a phone check is sharp, and on a small house lot it isn't. Below about a quarter of an acre, a measuring tape along each side will tell you more than any GPS.

Worked example: a "5 acres, more or less" field

The deed says 5.00 acres. You tap the corners on the satellite map and get 4.82 acres, which is 0.18 acre short, about 728 m² or 7,840 ft². That's 3.6%, and it looks like a lot of land.

Now run the test. The field is roughly 200 × 101 m, so the perimeter is about 602 m. The corners are clear fence posts, but one side runs along a hedge, so ±2 m on the edges is fair. The band is 602 × 2 = 1,204 m², or about 0.30 acre.

The 0.18 acre gap sits well inside it. Your measurement agrees with the deed as closely as a phone can show. If you'd got 4.40 acres instead, 0.60 acre short and twice the band, you'd have a real question to chase.

Walking the boundary as a second check tightens the picture. If the walk gives 4.88 acres and the map gave 4.82, the two methods agree with each other, and both agree with the deed within the band.

Measuring with Field Maps with Area Measure

Field Maps with Area Measure gives you both methods in one place: tap points on the satellite map, with a magnifier loupe for placing corners precisely, or walk, drive or fly the boundary and let the app record the path and close the shape. It shows area and perimeter in acres, hectares, m², square feet and more, and you can save each measurement with a name so the map and walked versions sit side by side. It runs on iPhone and iPad (iOS 17 or later); there's no Android version yet.

Why your measurement and the deed disagree

When the gap is bigger than the error band, the cause is usually one of these:

• The fence isn't on the boundary. Fences get built a few feet inside the line to keep them off a ditch, or drift over decades of repairs. Across a 200 m side, a fence 3 m inside the line costs 600 m², about 0.15 acre.
• Land was taken or added. Road widening, a utility easement, a strip sold to a neighbour years ago, or a stream that moved.
• The boundary runs somewhere you didn't measure. Some deeds run to the centre of a road or stream, not its edge.
• An old or rounded survey. "5 acres more or less" may simply have been rounded when the deed was first drawn up.
• Unit mix-ups. Hectares read as acres (a factor of 2.47), or square feet copied as square yards.
• Slope, rarely. Phone apps, like most surveys and maps, give horizontal area. On a steady 15% slope the actual ground surface is about 1.1% larger, which explains a small gap on hilly land but never a big one.

What to do with the result

If your figure is inside the band, you're done: the deed and the ground agree. If it's well outside, check the likely causes above first, measure a second time by the other method, and look at old aerial images or the plat if you can get them. For a sale, a dispute, a boundary line or anything else with legal weight, the next step is a licensed land surveyor. A phone measurement is an estimate and doesn't replace the survey or the official records. It does tell you whether to call one.

FAQ

How do I check my land area online?

Find your plot on a satellite map, place a point on each corner and read the area. A dedicated app makes this easier on a phone and also lets you walk the line. Compare the result with your deed using the error-band test above.

Is the acreage on a deed always accurate?

No. Deed acreage is often copied from old surveys and may be rounded or followed by "more or less". A recent survey by a licensed surveyor is the most reliable figure.

How big a difference from the deed is normal?

On a few acres, a phone measurement within 3–6% of the deed is normal. Use perimeter × edge accuracy for your own plot: the smaller the plot, the larger the normal percentage.

Can a phone measurement settle a boundary dispute?

No. It can show whether something looks wrong, but only a licensed surveyor can establish a legal boundary.