How to Calculate Roofing Squares and Shingle Bundles (With Examples)
Published 2026-10-24
Roofers don’t talk in square feet. They price jobs, order shingles and compare quotes in squares. Knowing how to work out the number of squares on your own roof helps you check a contractor’s quote, plan a DIY reroof or order the right amount of shingles for a shed. You can do it from the ground, without climbing a ladder.
What is a roofing square?
One roofing square is 100 square feet of roof surface. A roof with 2,000 square feet of surface is a 20-square roof. Standard asphalt shingles are packed so that three bundles cover one square, although some heavier architectural shingles need four or more, so always check the wrapper.
Step 1: measure the footprint
Measure the length and width of the house, then add the overhang on each side, because the eaves are roofed too. An overhang of around 1 foot is common. You can measure along the walls with a tape, take the dimensions from the house plans, or measure the roof outline on an online satellite map.
Example: a 40 × 30 ft house with a 1 ft overhang has a footprint of 42 × 32 = 1,344 square feet.
Step 2: find the roof pitch
Pitch is how many inches the roof rises for every 12 inches it runs horizontally. A 6/12 roof rises 6 inches per foot. The easiest way to measure it is from inside the attic: hold a level horizontally against the underside of a rafter, mark 12 inches along the level, and measure straight up from that mark to the rafter. That measurement in inches is the rise. Many US homes fall between 4/12 and 9/12.
Step 3: apply the pitch multiplier
A sloped roof has more surface than the ground it covers. The steeper it is, the bigger the difference. Multiply the footprint by the pitch multiplier:
| Pitch | Multiplier | Pitch | Multiplier |
|---|---|---|---|
| 3/12 | 1.031 | 8/12 | 1.202 |
| 4/12 | 1.054 | 9/12 | 1.250 |
| 5/12 | 1.083 | 10/12 | 1.302 |
| 6/12 | 1.118 | 12/12 | 1.414 |
| 7/12 | 1.158 |
The multiplier comes from the Pythagorean theorem: √(1 + (rise ÷ 12)²). For our example, 1,344 × 1.118 = about 1,503 square feet of roof.
Step 4: convert to squares and add waste
Divide the roof area by 100: 1,503 ÷ 100 = 15.0 squares. Then add a waste allowance, because shingles are cut at edges, valleys and ridges:
- About 10% for a simple gable roof (two sloped sides).
- About 15% for a hip roof, where all four sides slope and more cutting is needed.
- Up to 20% for complex roofs with dormers, valleys and several levels.
Our gable example becomes 15.0 × 1.10 = 16.5 squares. Round up to 17 squares.
Step 5: work out the bundles
At three bundles per square, 16.5 squares × 3 = 49.6, so buy 50 bundles. Starter strips and ridge cap shingles are usually separate products, sold by the linear foot they cover, so measure the eaves, rakes and ridges and add those to the order.
The roofing calculator runs all five steps at once: enter the footprint, overhang, pitch and waste, and it gives you the roof area, squares and bundles.
What else to measure
- Underlayment goes under the shingles and is sold in rolls labeled with the number of squares they cover. Divide your squares by that number.
- Drip edge runs along the eaves and rakes and is sold in lengths, commonly 10 feet.
- Ridge vents, flashing and nails depend on the roof design; a supplier can work these out from your squares and roof shape.
Using squares to check a quote
Contractors often quote a price per square, which makes quotes easy to compare once you know your own number. If two quotes list very different square counts for the same roof, ask how each one measured it; the difference usually comes from the pitch or the waste allowance. NerdWallet’s roof cost guide puts asphalt shingle roofs at roughly $4.25 to $12.25 per square foot installed, which is about $425 to $1,225 per square, with labor making up around 60% of the total. Local prices vary a lot, so treat that as a rough check rather than a target.
To compare quotes as a percentage difference, the percentage calculator helps.
Common questions
- How many squares is a 2,000 sq ft house? It depends on the pitch and overhang, not just the floor area. A single-story 2,000 sq ft home with a 6/12 roof and 1 ft overhangs usually has roughly 24 to 25 squares before waste. A two-story house with the same floor area has a much smaller footprint, and so fewer squares.
- How much does one bundle of shingles cover? About 33.3 square feet for most standard shingles, which is why three make a square.
- Do I measure each side of the roof separately? For simple gable and hip roofs, the footprint-and-pitch method gives the same answer with less work. Measure separately when sections have different pitches.
- Is it safe to measure on the roof? Measuring from the ground or the attic avoids the risk. If you do go up, use proper fall protection, and never climb a wet or steep roof.