Guides › Updated 2026-10-31
Area and Acreage Math for the Real Estate Exam: Acres, Triangles, Sections
TL;DR: Get everything into the same unit before you multiply. Key numbers: 43,560 sq ft = 1 acre, 9 sq ft = 1 sq yd, 27 cu ft = 1 cu yd, 640 acres = 1 section. Break odd shapes into rectangles and triangles, then add or subtract.
Constants to memorize
| Fact | Value |
|---|---|
| 1 acre | 43,560 sq ft |
| 1 sq yd | 9 sq ft |
| 1 cu yd | 27 cu ft |
| 1 section | 640 acres (1 square mile) |
| 1 township | 36 sections (23,040 acres) |
| 1 mile | 5,280 feet |
Quick check on the section: 5,280 x 5,280 = 27,878,400 sq ft, and 27,878,400 / 43,560 = 640 acres.
Basic shapes
- Rectangle: length x width
- Triangle: 1/2 x base x height (height is the perpendicular distance)
- Perimeter (fencing, trim): add all the sides, or 2 x (L + W) for a rectangle
Example: Triangular lot
A lot has a base of 120 feet and a height of 80 feet.
1/2 x 120 x 80 = 4,800 sq ft. The wrong answer 120 x 80 = 9,600 forgets the half.
Square feet to acres
Divide by 43,560.
Example: Acreage and price
A rectangular parcel is 660 feet by 1,320 feet and land sells for $4,500 per acre.
- Area: 660 x 1,320 = 871,200 sq ft
- Acres: 871,200 / 43,560 = 20 acres
- Value: 20 x $4,500 = $90,000
Going the other way, 2.5 acres is 2.5 x 43,560 = 108,900 sq ft. A lot 165 feet wide and 660 feet deep gives 165 x 660 = 108,900 sq ft, so it is exactly 2.5 acres.
Square yards (carpet, sod, paving)
Pricing is often per square yard while the room is measured in feet.
Example: Carpet
A room is 15 feet by 12 feet and carpet costs $28 per square yard installed.
- Area: 15 x 12 = 180 sq ft
- Square yards: 180 / 9 = 20 sq yd
- Cost: 20 x $28 = $560
The mistake to avoid is multiplying 180 by $28 (which gives $5,040) because the units do not match.
Irregular and L-shaped lots
Split the shape into rectangles (and triangles), find each area, then add. Or take a large rectangle and subtract the missing piece.
Example: L-shaped lot
A 200-foot by 150-foot rectangle has a 50-foot by 40-foot corner removed.
- Subtract method: 200 x 150 = 30,000; 50 x 40 = 2,000; 30,000 - 2,000 = 28,000 sq ft
- Add method: split into a 200 x 110 rectangle (22,000 sq ft) and a 150 x 40 rectangle (6,000 sq ft); 22,000 + 6,000 = 28,000 sq ft
Both methods agree, which is a good habit: solve it two ways when time allows.
Example: Fencing
A 165-foot by 660-foot lot needs fencing on all four sides at $12 per foot. Perimeter: 2 x (165 + 660) = 1,650 feet; 1,650 x $12 = $19,800.
Cubic yards (concrete, fill)
Convert all dimensions to feet first, multiply for cubic feet, then divide by 27.
Example: Concrete slab
A slab is 30 feet by 24 feet and 4 inches thick.
- Thickness: 4 / 12 = 1/3 foot
- Volume: 30 x 24 x 1/3 = 240 cu ft
- Cubic yards: 240 / 27 = 8.89 cu yd (about 8.9)
Real orders round up for waste, but a math question will usually ask for the computed figure.
Section and township fractions
Read the description from the end backward and multiply the fractions, then multiply by 640.
| Description | Fractions | Acres |
|---|---|---|
| NE 1/4 of a section | 0.25 | 640 x 0.25 = 160 |
| SE 1/4 of the NE 1/4 | 0.25 x 0.25 | 640 x 0.0625 = 40 |
| N 1/2 of the SW 1/4 | 0.5 x 0.25 | 640 x 0.125 = 80 |
| S 1/2 of the NW 1/4 of the SE 1/4 | 0.5 x 0.25 x 0.25 | 640 x 0.03125 = 20 |
Example: Value of a section fraction
The SE 1/4 of the NE 1/4 is 40 acres. At $3,200 per acre: 40 x $3,200 = $128,000.
Common mistakes
- Mixing inches and feet in a volume problem.
- Dividing square feet by 3 instead of 9.
- Forgetting the 1/2 in a triangle.
- Reading a legal description left to right instead of from the end backward.
- Treating all lots as rectangles when the question shows a corner cut out.
Land measurement ties into value too: price per acre, price per sq ft and front-foot value are all in the formulas cheat sheet and the formulas reference.
Practice
Draw every shape on scratch paper and label the units. Then try the free quiz for your state, such as Texas, Florida, California or New York, or use the GablePrep app for step-by-step solutions.
GablePrep is an independent study resource, not affiliated with any state real estate commission or testing provider. We are not a pre-licensing course and this is not legal advice. Confirm which land-description topics your exam covers in your state’s handbook.
Frequently asked questions
How many square feet are in an acre?
43,560 square feet. Memorize it; exams may or may not print it in the question.
How many acres are in a section?
A standard section is one square mile, or 640 acres. A township is 36 sections, which is 36 square miles or 23,040 acres. Fractions of a section are found by multiplying the fractions together and then multiplying by 640.
How do you convert square feet to square yards?
Divide by 9, because a square yard is 3 feet by 3 feet. For cubic yards, divide cubic feet by 27.
Will my exam test the rectangular survey system?
Content outlines vary by state, and not every state uses the rectangular (section and township) system. Check your state's candidate handbook for whether legal descriptions and section fractions are tested.
Independent exam prep. Not affiliated with any state real estate commission or testing provider. Not an approved pre-licensing course. Not legal advice. Facts verified on 2026-10-31; always confirm with your state’s official handbook.