Acreage · Measuring land · Field tips · October 18, 2026

How to Measure an Acre of Land: Feet, Shapes and Pacing

How to measure an acre of land: an acre is 43,560 sq ft, about 208.7 feet square. Dimensions for other lot shapes, pacing it off and using map tools.

How to measure an acre of land: start with the number that never changes. An acre is 43,560 square feet of ground, in any shape. Laid out as a square, that is about 208.7 feet on each side. You can mark one out with a long tape or a measuring wheel, get close by pacing, or trace it on a map tool. This guide gives the dimensions of an acre in common lot shapes, walks through measuring one on the ground, shows how to handle odd-shaped pieces and explains where a homemade measurement stops and a survey has to take over.

The short answer

One acre = 43,560 square feet, which is also 4,840 square yards and about 4,047 square meters.
Square acre: about 208.7 × 208.7 feet, with a perimeter of about 835 feet.
Any rectangle works: depth = 43,560 ÷ frontage. A lot 100 feet wide needs to be 435.6 feet deep to hold an acre.
Measure flat, not along the slope. Acreage is horizontal area, the way it would look on a map.
Measuring is not surveying. A tape, a wheel or a map tool tells you size; only a licensed surveyor can tell you where your legal lines are.

How big is an acre?

The acre is a unit of area, not length, so it has no fixed shape. The official US definition, listed in the National Institute of Standards and Technology’s tables of units (Handbook 44, Appendix C), is 43,560 square feet. The same tables give two older ways of saying it that still show up in deeds and plats:

10 square chains. A surveyor’s chain is 66 feet, so a strip 1 chain wide and 10 chains long, 66 × 660 feet, is exactly one acre. 660 feet is also a furlong. See what is a chain in land measurement.
160 square rods. A rod is 16.5 feet, so a square rod is 272.25 square feet. See what is a rod in land measurement.

Bigger units build on the acre too: a square mile, or a standard section, is 640 acres. More on that in how many acres are in a section.

Dimensions of one acre in different shapes

Every shape below holds 43,560 square feet. The rule for rectangles is simple: pick the width and divide 43,560 by it to get the length.

Square: 208.71 × 208.71 feet
One chain by one furlong: 66 × 660 feet
Narrow strip: 50 × 871.2 feet
Common rural frontage: 100 × 435.6 feet
Wider lot: 150 × 290.4 feet
Nearly square: 200 × 217.8 feet
Circle: radius about 117.75 feet, diameter about 235.5 feet
Right triangle with two equal sides: legs about 295.2 feet each

Long, narrow shapes need a lot more fence for the same acre. The square needs about 835 feet of perimeter, while the 50 × 871.2 foot strip needs about 1,842 feet. If you are working out how many building lots fit on a larger piece, see how many lots per acre.

How to measure an acre on the ground

You need a long tape (100 or 300 feet) or a measuring wheel, four stakes or flags, string and a helper if you can get one.

Pick a straight starting line, such as a road edge, fence or driveway, and drive a stake at the first corner.
Measure the first side. For a square acre that is 208.7 feet. For a rectangle, choose the width and work out the length with 43,560 ÷ width.
Turn a right angle at each corner with the 3-4-5 rule: measure 30 feet along one side and 40 feet along the other, then move the second line until the distance between those two points is exactly 50 feet. Larger multiples such as 60-80-100 are more accurate over long sides.
Measure the remaining sides and set the last two stakes.
Check the diagonals. In a true rectangle both diagonals are equal. For a square acre each one should be about 295.2 feet. If they differ, nudge the corners until they match.

On a slope, keep the tape as level as you can, or measure in shorter level steps. A tape laid along the surface of a hillside reads long, so a staked “acre” on a steep hill will cover less than an acre of map area.

Pacing off an acre

Pacing will not give you a legal measurement, but it gets you close enough to picture a piece of land on a walk-through.

Measure out 100 feet on flat ground with a tape.
Walk it at your normal stride and count your steps. Do it two or three times and average the count.
Divide 100 by your count to get feet per step. At 40 steps per 100 feet, each step is 2.5 feet.
Divide 208.7 by your step length. At 2.5 feet per step, one side of a square acre is about 83 steps.

Rough ground, tall grass, hills and fatigue all shorten a stride, so expect pacing to be off by a noticeable margin. Use it for a feel, never for a purchase or a fence line.

Measuring an irregular piece

Real parcels are rarely perfect rectangles. To estimate the area of an odd shape:

Break it into simple pieces. Split the shape into rectangles and triangles, measure each one and add the areas together.
Use the triangle formula for angled corners: area = ½ × base × height, where the height is measured at a right angle to the base.
Divide the total by 43,560 to convert square feet to acres.
Be careful with shortcuts. Averaging opposite sides and multiplying them only works well for shapes close to a rectangle. On a skewed four-sided lot it overstates the area.

If the land is already recorded, the plat or deed usually lists the bearings and distances of every line, and the county parcel record often shows a calculated acreage. Our guide on how to find a property’s acreage explains which of those numbers to trust, and how to read a parcel map helps you find the line lengths.

Measuring an acre on a map

Google Earth has a measure tool that shows the area once you close a shape. Google notes its measurements do not account for changes in elevation and work best from a top-down view.
Google My Maps can also measure distances and areas when you draw a shape.
Regular Google Maps measures distance between points but does not report the area, so you would multiply side lengths yourself.
County GIS parcel viewers often include a measure tool, and many list calculated acres for each parcel. Our land map links to county parcel viewers.

Map tools are only as good as the imagery and parcel lines underneath. Parcel layers can sit several feet off the real boundary, and photos can be shifted or taken at an angle. See why Google Earth does not show official lot lines.

When measuring is not enough

A tape or a map tells you how big an area is. It does not tell you where your property begins and ends. That depends on the deed, the plat and the corners a surveyor sets or finds. Hire a licensed land surveyor before you build near a line, put up a fence, split off land or buy or sell by the acre. If you just want to locate existing markers, start with how to find property corners, and keep in mind why a handheld GPS is not a survey.

Getting a feel for the size

An American football field from goal line to goal line, 300 × 160 feet, is 48,000 square feet, so an acre is a little over nine-tenths of the playing field.
Counting both end zones, the field is 360 × 160 feet, and an acre is about three-quarters of it.
A square acre takes about 835 feet of walking to go all the way around.

Questions people ask

How many feet is an acre on each side?

If the acre is a perfect square, each side is about 208.71 feet. Other shapes have different side lengths, as long as the area adds up to 43,560 square feet.

How many square feet are in an acre?

An acre is 43,560 square feet, which is the same as 4,840 square yards, 10 square chains or about 4,047 square meters.

How do I pace off an acre?

Walk a measured 100 feet a few times and count your steps to find your step length. Then divide 208.7 by that length to get the steps for one side of a square acre. It is only a rough estimate.

Can I measure an acre on Google Maps?

Regular Google Maps measures distance but not area, so you would multiply side lengths yourself. Google Earth and Google My Maps can show the area of a shape you draw, but imagery and parcel lines are approximate.

What are the dimensions of a 1 acre lot?

Any length and width that multiply to 43,560 square feet. Common examples are 208.7 by 208.7 feet, 100 by 435.6 feet, 150 by 290.4 feet and 66 by 660 feet.

Is measuring my land the same as a survey?

No. Measuring tells you how big an area is. Only a licensed land surveyor can locate or set your legal property corners and lines based on the deed and plat.