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Roofing & Siding Calculators

Roof area, shingles, pitch, siding and gutters.

Roofing is measured in squares of 100 square feet, and the roof is always bigger than the house footprint because of the slope. The calculators here convert ground measurements and pitch into roof area, then into bundles of shingles, metal panels, underlayment, ridge cap and the trim around the edges.

Pitch is the key input. A 6/12 roof has 12 percent more surface than its footprint, a 12/12 roof has 41 percent more. Add 10 percent waste for a simple gable and 15 to 20 percent for hips, valleys and dormers, where every cut shingle is a partial loss.

How much material do I need

Quantities to order, in the units a supplier sells them in. 9 calculators.

Roofing CalculatorCalculate roof area, roofing squares and how many bundles of shingles you need from your home's footprint and roof pitch. Includes underlayment and waste.Shingle CalculatorCalculate how many bundles of shingles you need from your roof area, plus ridge cap bundles, starter strip bundles and pounds of roofing nails, with waste included.Metal Roofing CalculatorCalculate how many metal roofing panels, screws, closure strips and ridge cap you need from the eave length, panel length and panel coverage width, with waste.Rafter Length CalculatorCalculate common rafter length from the building span and roof pitch, including the ridge board deduction and overhang, plus the rise, cut angle and board length to buy.Siding CalculatorCalculate how many squares and boxes of vinyl siding you need from your house dimensions, plus starter strip, J-channel and corner posts, minus doors and windows.Gutter CalculatorCalculate how many gutter sections, downspouts, hangers, end caps and elbows you need from the total eave length, with an optional material cost per linear foot.Soffit and Fascia CalculatorCalculate soffit area and panels, fascia board length and 12 ft pieces, plus J-channel and F-channel for the eaves and gable rakes of a house from a few measurements.Roof Truss CalculatorRoof truss calculator for a gable or hip package: truss count with the girder and step-down hip set, bracing lumber, hurricane ties and a cost range by truss type.Hip Roof CalculatorThis hip roof calculator gives ridge length, common and hip rafter lengths, the jack rafter common difference, the hip backing bevel angle and total sloped roof area.

What size do I need

Sizing and specification, against the code or standard that governs it. 2 calculators.

Roof Pitch CalculatorRoof pitch calculator that converts both ways: rise over run, total rise and span, degrees or slope percent into x/12, plus the ridge height for a pitch you pick.Roof Snow Load CalculatorCalculate the design roof snow load from the ground snow load, roof pitch, exposure and thermal factors using the ASCE 7 method, plus the total snow weight on the roof.

What will it cost

Line item budgets built from current US material and labor rates. 3 calculators.

Metal Roof Cost CalculatorPrice a metal roof by profile, metal, thickness, tear-off and complexity. Covers steel, aluminum, copper and zinc, with a total range and a cost per square.Gutter Cost CalculatorUse this gutter cost calculator to price a full system by the linear foot: gutter style and material, downspouts, height, gutter guards and removal of the old gutters.Roof Replacement Cost CalculatorRoof replacement cost calculator for asphalt shingles. Prices tear off, disposal, deck repair, underlayment, ice barrier, shingles and labor by pitch and story.

A typical project, in order

Carry each result into the next tool.

  1. 1Roof Pitch CalculatorFind the pitch and its area multiplier
  2. 2Roofing CalculatorRoof area and bundles from the footprint
  3. 3Shingle CalculatorBundles, starter, ridge cap and nails from roof area
  4. 4Rafter Length CalculatorRafter lengths for a new roof frame
  5. 5Gutter CalculatorSections, downspouts and hangers
  6. 6Soffit and Fascia CalculatorFinish the eaves
  7. 7Siding CalculatorSquares of siding for the walls below

Roofing & Siding questions

How many bundles of shingles per square?

Three for standard 3-tab and most architectural shingles. Some thick designer shingles need four or five; the wrapper states bundles per square.

How do I find my roof area without climbing on it?

Measure the house footprint including overhangs, then multiply by the pitch factor: 1.054 for 4/12, 1.118 for 6/12, 1.202 for 8/12, 1.414 for 12/12.

How much waste for a roof?

10% for a plain gable roof, 15 to 20% for hip roofs and roofs with valleys, dormers or skylights.