Shingles Calculator

Ran the Roof calculator already? Keep Active project selected to reuse that area. Otherwise switch to Manual and type your own square footage.

Chained roof area

Run the roof calculator first to prefill shingles with the active project roof area.

Pick the shingle profile you're installing — this changes the default coverage assumptions.

Roof areasq ftTotal roof area to cover, in square feet.

Know bundles needed per 100 sq ft square? Use Bundles per square. Know how much one bundle covers instead? Use Sq ft per bundle.

Bundles per squarebundlesNumber of bundles that cover one roofing square (100 sq ft). Check the shingle wrapper.Waste percent%Extra material to cover cuts and mistakes. 10% is typical for a simple roof, more for a cut-up roof.

Accessories

Optional — enter eave, rake, ridge, hip, and valley lengths to size starter strip, drip edge, cap shingles, and valley flashing. Underlayment is sized from roof area either way.

Eave lengthoptionalftTotal length along the roof's lower edges (eaves).Rake lengthoptionalftTotal length along the roof's sloped edges (rakes).Ridge lengthoptionalftTotal length along the roof's peak (ridge).Hip lengthoptionalftTotal length of all hips. Cap shingles run the hips as well as the ridge, and on a low hip roof the hips are the longer of the two. Leave blank if this roof has none.Valley lengthoptionalftTotal length of all valleys, for valley flashing. Where an ice barrier is required, this also runs one 36 in course down each valley. Leave blank if this roof has none.Valley flashing stock lengthoptionalftLength one piece of valley flashing ships in. Defaults to 10 ft; the joints between pieces are what the lap below is added for.Valley flashing end lapoptionalinEnd lap where two pieces of valley flashing meet. Defaults to 6 in — a common manufacturer instruction, not an IRC requirement. Check your product's instructions.Underlayment coverage per rolloptionalsq ftSquare footage one roll of underlayment covers. Left blank this uses 400 sq ft — a No. 15 felt roll after its salvage lap. Synthetic underlayment usually ships nearer 1,000 sq ft, so check the wrapper.

Ice barrier, ventilation, and fasteners

Optional. Nothing here is guessed for you -- an ice barrier is a local code question and ventilation is measured off the attic floor, not the roof.

Ice barrier coursesoptionalCourses of 36 in membrane along the eave. IRC R905.1.2 requires an ice barrier only where there is a history of ice forming at the eaves, so this is left to you rather than assumed either way.Attic floor areaoptionalsq ftThe flat ceiling area below the attic, not the sloped roof above it. IRC R806.2 sizes ventilation against this.Ventilation ratio (1 in ...)optional150 is the base IRC R806.2 rule. Enter 300 only if BOTH exception conditions are met: 40-50% of the required vent area comes from ventilators in the upper attic, no more than 3 ft below the ridge measured vertically, with the balance at the eaves; and, in Climate Zones 6-8, a Class I or II vapor retarder is on the warm-in-winter side of the ceiling.Ridge vent net free areaoptionalsq in per ftRead it off the ridge vent you are buying -- vent products print net free area on the carton and the spec sheet, almost always in square inches per linear foot. Left blank on purpose: it varies several-fold with the vent's width, so nothing is assumed here. Leave it blank and the ridge vent is reported as a material to price yourself.Intake vent net free areaoptionalsq in per unitRead it off the intake vent you are buying -- vent products print net free area on the carton and the spec sheet. Enter it per vent for a discrete louvre or block vent, or per linear foot for a continuous strip, and count that same unit. Left blank on purpose: two vents of the same face size can differ several-fold once the louvre pattern and the insect screen are accounted for, so nothing is assumed here. Leave it blank and the intake vents are reported as a material to price yourself.Fasteners per squareoptional320 is four nails into each of about 80 shingles, the IRC R905.2.6 minimum. Use 480 for a six-nail pattern in high-wind areas.Underlayment cap fasteners per squareoptionalCap nails or cap staples per square for the UNDERLAYMENT -- read it off that product's installation instructions. Left blank on purpose: synthetic underlayments differ several-fold in the pattern they require, and the IRC sends you to the manufacturer rather than fixing one, so nothing is assumed. Leave it blank and the cap fasteners are reported as a material to price yourself.

Enter a roof area and this will say how much roofing to buy.

You'll need

Shingle estimate

Warnings

INFO No roof area is saved in the active project yet. Type one into Roof area below, or run the roof calculator first.
INFO Enter eave, rake, ridge, hip, and valley lengths to size starter strip, drip edge, cap shingles, and valley flashing. These are skipped without them.

Not counted -- answer these to add them

Ridge and soffit ventilation: The attic floor area. IRC R806.2 sizes ventilation against the flat ceiling below, not the sloped roof above, so the roof area entered here cannot stand in for it.

Detail values

Roof area used: — sq ft
Squares: —
Adjusted squares: —
Fasteners: —
Underlayment cap fasteners: pattern not entered — see the material gaps
Required vent area: attic floor area not entered
Soffit / intake vents: attic floor area not entered

Assumptions

Shingle type: Architectural / dimensional
Coverage input: Bundles per square
Estimated waste: 10% for an average project
Underlayment coverage: 400 sq ft per roll -- a No. 15 felt roll (36 in x 144 ft) after its salvage lap. Synthetic underlayment usually ships nearer 1,000 sq ft; check the wrapper and change this.
Valley flashing lap: valley length not entered -- valley flashing not counted
Ice barrier: not entered -- membrane not counted
Ice barrier roll coverage: 200 sq ft per roll -- a 36 in x 66.7 ft roll. No field for it on this screen yet; check the wrapper before ordering.
Underlayment cap fasteners: not entered -- cap nails/staples not counted
Ventilation ratio: attic floor area not entered -- ventilation not sized
Ridge vent net free area: not entered -- ridge vent not counted
Intake vent net free area: not entered -- intake vents not counted
Fasteners: 320 per square -- four nails into each of the ~80 strip shingles a square takes at a 5 in exposure (IRC R905.2.6 minimum)

Included: roofing material, underlayment, waste allowance, fasteners.

Not included: labor, delivery, permits, disposal of waste material.

Formula details

Squares: roofArea / 100
Adjusted squares: squares x (1 + wastePercent)
Bundles to buy: ceil(adjustedSquares x bundlesPerSquare)
Drip edge: eaveLength + rakeLength
Ridge cap: ridgeLength + hipLength
Cap shingles run the ridge and every hip off the same bundle, so they are one length. A hip roof's hips are often longer than its ridge, and the roof area cannot tell them apart -- a gable and a hip roof of equal area measure the same.
Valley flashing: valleyLength + (ceil(valleyLength / stockLength) - 1) x endLap
One end lap at each joint between 10 ft pieces. The 6 in lap is a common manufacturer installation instruction, not an IRC dimension -- the code sends you to the manufacturer's instructions for valley lining. Check your product and change it here if it differs.
Underlayment rolls: ceil(adjustedArea / coveragePerRoll)
Ice barrier area: (eaveLength x 3 ft per course x courses) + (valleyLength x 3 ft)
IRC R905.1.2. Required only where there is a history of ice forming along the eaves. Where it is required, each valley gets one 36 in course down its centreline -- that 3 ft is the membrane's own width, not a second assumption about how far up the valley it runs.
Required net free vent area: atticFloorArea / 150 x 144
IRC R806.2. The 1/300 ratio applies only where BOTH exception conditions are met: 40 to 50 percent of the required ventilating area comes from ventilators in the upper portion of the attic, no more than 3 ft below the ridge measured vertically, with the balance at the eaves; and, in Climate Zones 6, 7 and 8, a Class I or II vapor retarder is installed on the warm-in-winter side of the ceiling. Otherwise the ratio is 1/150.
Roofing nails: ceil(adjustedSquares x fastenersPerSquare)
IRC R905.2.6 sets not less than four fasteners per strip shingle, or two per individual shingle, as the minimum; six is required in high-wind areas and wherever the manufacturer says so. R905.2.5 governs the nail itself (gauge, head, penetration), not how many.

Material List

About this calculator

Pull roof area from the active project or override it manually when you're pricing a roof from field notes.

FAQ

Can I use this without the roof calculator?

Yes. Switch to manual area and enter the square footage directly.

What if my product lists square feet per bundle?

Choose the square-feet-per-bundle mode and CrewMeasure converts the adjusted roof area into bundles to buy.

Should I always add waste?

Usually yes. Waste covers cuts, hips, valleys, and handling losses, but you can set the percentage yourself.

How does metal panel work differently from shingle bundles?

Selecting Metal panel switches the primary quantity to panel count, computed as the adjusted roof area divided by your panel's covered area (editable), rounded up — panels are commonly custom-cut to the rafter length, so this sizes how many panel-widths span the roof rather than a bundle count.

Do I have to enter eave, rake, and ridge length?

No — they're optional. Without them you still get bundles/panels and underlayment (both area-based). Enter them to also size starter strip, drip edge, and ridge cap.

Roof area source