Roofing Size Calculator
Enter the sloped area of your roof, the length of ridge and the type of shingle, and choose a waste allowance. The calculator works out the squares, bundles, underlay rolls, nails and ridge cap to order.
- Squares and bundles
- Underlay and nails
- Waste allowance
Use the sloped roof area. If you only know the footprint, work out the roof area first with the roof size calculator.
Roofing is ordered by the square, 100 square feet of roof. Most asphalt shingles come three bundles to a square. Add 10% for a simple roof and 15% for one with hips and valleys, because shingles are cut and wasted at every edge.
Roofing material chart
Architectural shingles, 10% waste. Search for a roof size.
| Roof (sq ft) | Squares | Bundles | Underlay rolls | Nails |
|---|---|---|---|---|
| 1000 | 11 | 33 | 2 | 3520 |
| 1500 | 16.5 | 50 | 2 | 5280 |
| 2000 | 22 | 66 | 3 | 7040 |
| 2500 | 27.5 | 83 | 3 | 8800 |
| 3000 | 33 | 99 | 4 | 10560 |
| 4000 | 44 | 132 | 5 | 14080 |
Underlay rolls are synthetic at about 10 squares a roll.
Squares and bundles
Architectural shingles. Slide the roof area.
Each block in the stack is ten bundles of shingles.
How to work out roofing
From roof area. Step through it.
Roof area
Sloped, in sq ft.
Starter strip goes along the eaves and rakes. Many installers cut it from ordinary shingles or buy one bundle for every 100 feet.
Three-tab, architectural or designer
Shingle types. Compare them.
Flat, single layer.
Laminated, layered look.
Heavy, slate or shake look.
Architectural shingles cost more than three-tab but last longer and stand up to stronger winds.
Before ordering
Roofing checklist. Tick each item.
Tick each item as you go.
Ask the supplier if they take back unopened bundles. That makes it safe to order a little extra.
What you get
Your order list. Each tile explains one result.
Area ÷ 100.
For the shingle.
Rolls to buy.
Four a shingle.
Bundles.
Bundles of designer shingles can weigh 90 lb each. Check the roof can be loaded safely before delivery.
Frequently Asked Questions
No question matches that search.
How many bundles of shingles are in a square?
Three for most three-tab and architectural shingles, and four or five for heavy designer shingles.
How do I work out roofing squares?
Divide the sloped roof area in square feet by 100.
How much waste should I allow for shingles?
About 10% for a simple gable roof and 15% or more for hips, valleys and dormers.
How many nails do I need per square?
About 320, four per shingle, or six per shingle in high wind areas.
How much underlay do I need?
A synthetic roll covers about 10 squares and a roll of felt about 4.
How much ridge cap should I buy?
About one bundle for every 33 feet of ridge and hips.
Is roof area the same as floor area?
No. The roof is bigger because it slopes and overhangs the walls.
Order the right amount of roofing
Start from the roof area, add waste for the shape and get bundles, underlay, nails and ridge in one list. Nothing runs short halfway up the ladder.
More size calculators
Each one has its own calculator, worked examples and answers to common questions.