A roof with 2,000 sq ft of surface needs 20 squares, which is 60 bundles of standard shingles before waste, or 66 bundles with 10% extra. The rule: one roofing square covers 100 sq ft, most 3-tab and architectural shingles come 3 bundles to the square, and you add 10–15% for cutting and waste. Starter strip and ridge cap are bought separately.
This calculator needs JavaScript. The formula and a worked example are explained in the article below.
Quick chart: shingle bundles by roof area
All figures assume 3 bundles per square and are rounded up to whole bundles. The first bundle column has no waste; the other two include 10% (simple gable roofs) and 15% (hips, valleys, dormers).
| Roof surface area | Squares | Bundles, no waste | Bundles +10% | Bundles +15% |
|---|---|---|---|---|
| 1,000 sq ft | 10 | 30 | 33 | 35 |
| 1,500 sq ft | 15 | 45 | 50 | 52 |
| 1,800 sq ft | 18 | 54 | 60 | 63 |
| 2,000 sq ft | 20 | 60 | 66 | 69 |
| 2,500 sq ft | 25 | 75 | 83 | 87 |
| 3,000 sq ft | 30 | 90 | 99 | 104 |
These numbers are for the field shingles only, the ones that cover the open planes of the roof.
How to measure the roof
You need the roof surface area, not the footprint of the house. A sloped roof is larger than the ground it covers, and the eaves and rakes hang past the walls.
GAF’s method is to measure the length and width of each roof plane, including dormers, multiply each pair, and add the results. That works if you have the plans or a roofer’s measurement report. If you don’t want to go up on the roof (and you shouldn’t, just to measure), work from the ground: take the footprint including the overhang and multiply it by the pitch multiplier. Our guide on how to calculate roof square footage walks through it, and the roof area calculator there gives you the number to type in here.
The formula
bundles = roof area (sq ft) × (1 + waste %) ÷ 100 × bundles per square
Round up to the next whole bundle. Supplies are usually sold by the bundle, so a fraction means one more.
A simple gable roof on a 40 × 30 ft house with 1 ft overhangs and a 6/12 pitch has about 1,503 sq ft of surface (from the roof area calculator).
Squares: 1,503 ÷ 100 = 15.03.
With 10% waste: 15.03 × 1.10 = 16.53 squares.
Bundles at 3 per square: 16.53 × 3 = 49.6, so 50 bundles.
If the roof had valleys or dormers, 15% waste gives 52 bundles.
Check bundles per square on the wrapper
Three bundles per square is the standard for most asphalt shingles, both 3-tab and architectural. GAF notes there are exceptions: some specialty shingles take up to five bundles per square because they are heavier. The wrapper or the product data sheet tells you the coverage per bundle, and the calculator has a bundles-per-square field. If the wrapper says 4 bundles per square, enter 4.
Don’t mix up a “square” of roof with the bundles in it. A square is always 100 sq ft of roof. The number of bundles needed to cover it depends on the product.
How much waste to add
GAF recommends adding 10–15% to the total for trim allowance and waste, and more for steep slopes or features such as rakes, valleys and dormers.
- 10%: a plain gable roof with two planes and few penetrations.
- 15%: hip roofs, valleys, dormers, skylights and chimneys, where many shingles are cut at an angle and the offcuts are too small to reuse.
- More than 15%: very steep or very cut-up roofs. Ask your roofer or supplier what they would order for that roof.
Starter strip and ridge cap are separate
The bundle count above covers the field. Two more products are ordered by the linear foot, not by the square:
- Starter strip runs along the eaves (and, in GAF’s system, the rakes) to help resist blow-offs at the edges. GAF’s Pro-Start provides about 120.33 linear feet per bundle. Starter strips replace the old practice of cutting up 3-tab shingles for the first course.
- Ridge cap covers the hips and ridges. GAF’s Seal-A-Ridge data sheet says 4 bundles cover about 100 linear feet, or roughly 25 linear feet per bundle.
Eaves: two sides of 42 ft = 84 ft. Rakes: four edges of about 17.9 ft (16 ft run × 1.118) = 71.6 ft.
Starter strip: 84 + 71.6 = 155.6 ft ÷ 120.33 = 1.3, so 2 bundles of Pro-Start.
Ridge: one ridge 42 ft long ÷ 25 = 1.7, so 2 bundles of Seal-A-Ridge.
Other brands list different coverage, so read the label for the starter and ridge products you buy.
When to call a roofer
Bundles are heavy and have to be carried up a ladder, and working on a roof is a real fall risk. GAF recommends hiring a professional roofing contractor to make sure the roof is installed correctly. Get one involved, at least for the measurement, if the roof is steep, has several levels, valleys, dormers or skylights, or if you need to tear off old layers. A contractor will also know your local code requirements and whether a permit is needed for a reroof.
Frequently asked questions
How many bundles of shingles are in a square?
For most standard asphalt shingles, 3-tab and architectural, it is three bundles per square (100 sq ft). Some heavy specialty shingles need four or five, so check the wrapper.
How many square feet does a bundle of shingles cover?
At three bundles per square, one bundle covers about 33.3 sq ft of roof. If your product is four bundles per square, each covers 25 sq ft.
How many bundles do I need for a 1,000 sq ft roof?
A 1,000 sq ft roof is 10 squares, or 30 bundles with no waste. With 10% waste it is 33 bundles, and with 15% it is 35.
Do I use the house’s square footage to order shingles?
No. The living area or footprint is smaller than the roof, because the roof is sloped and overhangs the walls. Multiply the footprint (including overhangs) by the pitch multiplier first, as explained in how to measure square footage for flat areas and our roof area guide for sloped ones.
