Shingle bundles for 900 sq ft of roof
These counts are for 900 sq ft of actual roof surface, measured on the slope. Most architectural and 3-tab shingles come three bundles to a square (100 sq ft); some heavier premium shingles take four. Suppliers sell whole bundles, so each count is rounded up.
| Waste allowance | Squares to order | Bundles (3 a square) | Bundles (4 a square) |
|---|---|---|---|
| None (exact) | 9.0 | 27 | 36 |
| 10% (simple gable) | 9.9 | 30 | 40 |
| 15% (hip, valleys) | 10.4 | 32 | 42 |
| 20% (complex roof) | 10.8 | 33 | 44 |
You will also need about 1 roll of synthetic underlayment (1,000 sq ft rolls with 10% for laps), plus starter strip along the eaves and rakes and ridge cap along the ridges and hips.
If 900 sq ft is the house footprint
Many people know the floor area of the house, not the roof. A roof covers the footprint plus the overhang, and the slope makes it larger again. For a 30 × 30 ft house (900 sq ft) with a 1 ft overhang, the roof covers 1,024 sq ft in plan, and the table shows how the pitch adds to that. Bundles include 10% waste, at three a square.
| Roof pitch | Roof area (sq ft) | Squares | Bundles |
|---|---|---|---|
| 4/12 | 1,079 | 10.8 | 36 |
| 6/12 | 1,145 | 11.4 | 38 |
| 8/12 | 1,231 | 12.3 | 41 |
| 10/12 | 1,333 | 13.3 | 44 |
| 12/12 | 1,448 | 14.5 | 48 |
The roofing calculator on this page opens on 900 sq ft of roof surface. To work from a house instead, switch "What do you know?" to the house footprint and enter its size, overhang and pitch, or read how to calculate roofing squares step by step.
Weight, nails and edge metal
Architectural shingles weigh about 60 to 80 lb a bundle, so 30 bundles are roughly 2,100 lb (1.1 tons) to lift onto the roof, which is the hard part of the job. Spread bundles across the roof's rafters, never stacked in one spot.
At about 320 nails a square (four per shingle), a 9.0 square roof uses around 2,880 nails, which is a 25 lb box or a couple of coils for a nail gun. Drip edge runs along the eaves and up the rakes: measure those edges and divide by 10 for the number of 10 ft pieces.
A 900 sq ft roof: three or four bundles a square?
900 sq ft of roof is 9.0 squares. With the usual three bundles a square that is 27 bundles, or 30 with 10% waste. Some heavier shingles are packed four bundles to a square, and the same roof then takes 36 bundles, or 40 with waste.
The difference of 10 bundles is not more roof, only smaller packs, so always compare prices by the square and not by the bundle. The number of bundles to a square, and the area one bundle covers, is printed on the wrapper; read it before you multiply, because an order worked out at the wrong rate is short by a quarter.
If the roof has hips or valleys
The 30 × 30 ft example house is square, and square houses are often built with a hip roof. The roofing calculator, given that footprint, counts 38 bundles for it at 10% waste. Raise the waste to 15%, the usual allowance where shingles are cut on a diagonal, and the count is 40 bundles.
So the hips cost about 2 more bundles of field shingles on this roof, and the hip cap is bought on top of that. A valley has the same effect: shingles on both sides are trimmed along the valley line and the cut-off pieces are seldom usable elsewhere.
Want to change anything else? The calculator above is the full Roofing Calculator: edit any number and the results update instantly.
Tools & materials for this project
Affiliate links As an Amazon Associate we earn from qualifying purchases. These links do not change what you pay.
Frequently asked questions
How many bundles of shingles do I need for 900 square feet?
900 square feet of roof is 9 squares. At three bundles a square that is 27 bundles exactly, so buy 30 bundles with 10% for waste on a simple gable roof, or 32 with 15% for a hip roof or one with valleys.
How many squares is 900 square feet of roof?
9 squares, because one roofing square is 100 square feet. With 10% waste you order 9.9 squares, which suppliers round to whole bundles: 30.
What if 900 sq ft is the size of my house, not the roof?
Then the roof is bigger, because it slopes and overhangs the walls. A 30 × 30 ft house (900 sq ft) with a 1 ft overhang and a 6/12 pitch has about 1,145 sq ft of roof, which is 11.4 squares and 38 bundles with 10% waste.
Related sizes and guides
Estimates only. Results assume standard materials and simple shapes. Supplier products vary, and the final call on quantity, structure and safety is yours. Check your local code and your supplier's guidance before ordering.