`RL = f( S,P,oH,BW)`

Enter a value for all fields

The Rafter Length calculator computes the length of the rafters based on the span, pitch and overhang.

INSTRUCTIONS: Choose units and enter the following:

• (S)  Span or horizontal length of the run (see diagram)
• (P) Pitch of Roof (choose one)
• (oH) Overhang
• (BW) Rafter Board Width (default: 5.5" for 2x6)

Rafter Length (RL): The rafter length is returned in feet.  The calculator also returns the Rafter Board Length (BL), which is the length of 2x needed prior to the angle cuts. However these can be automatically converted to other units via the pull-down menu.

The Math / Science

Using the pitch and the span, the initial rafter length is computed.  The calculator takes into consideration the 1.75 inches of the ridge board width.  There is then an adder for the additional length associated with the overhang.

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Gable Roof Calculators

• Gable Roof Area: This computes the surface area of a gable roof based on dimensions and pitch.
• Trusses Needed for Roof: This computes the number trusses need for a roof including gabled roof.
• 4x8 Sheathing for Gable Roof: This computes the total surface area of a roof, the number of 4x8s and framing nails needed for a gabled roof based on the length, span, pitch and overhang.
• Gable Roof Sheathing Cost: This computes the number of 4x8 sheets (32 ft² each) needed to cover a gabled roof based on the ridge length, roof span, overhang and the pitch and applies the unit cost of a 4x8.
• Nails for Gable Roof Sheathing: This computes the approximate number of nails needed to nail 4x8 sheets to trusses or rafters on a roof based on the dimensions of the roof, spacing of nails on the edges and field of the 4x8, and whether blocking or clips are use.
• Purlins for Gable Roof: This computes the total number and length of purlins for a simple gable roof based on the ridge length of the roof, the roof pitch and the span of the roof.
• Metal for Gable Roof: This estimates the metal panels and trim needed for a metal roof for a simple gabled roof based on the roof dimensions.
• Metal Screws for Gable Roof: This computes the number of special screws needed for a metal roof. 
• Shingles for Gable Roof: This computes the number of shingles (bundles), underlayment, ridge shingles, starter strip, and roofing nails for a gable roof.
• Gable Roof Shingle Cost: This estimates to shingle a basic gable roof based on dimensions (length, span, pitch and overhang) and the unit price of a bundle of shingles.
• Underlayment for Gable Roof: This estimates the cost of underlayment to cover a basic gable roof based on the area of a roof computed from the dimensions (length, span, pitch and overhang) and the unit price underlayment material. 
• Roofing Nails for Gable Roof: This estimates the number of roofing nails needed for a common gabled roof based on roof dimensions and wind conditions.
• Rafters for Gable Roof: This computes the total number of rafter boards (roof joists) for a gabled roof based on the ridge length, pitch and span.  It also returns the length of the ridge board, and the length and number of rafter ties and collar ties.
• Rafter Length: This computes the length of the rafters based on the span, pitch and overhang.
• Gable Roof Geometries: This computes the length of rafters, pitch and cut angles, soffit and facia base widths of a gable roof.
• Weight of Snow on Roof: This computes the weight of snow on a gable roof based on roof dimensions, depth and type of snow.

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Roof Types

Roofing Calculators

Gable Roof Area of Gable Roof Gable Roof 4x8 Sheathing Gable Roof Sheathing Cost Purlins for a Gable Roof Metal for a Gable Roof Screws for Metal Gable Roof Shingles for a Gable Roof Gable Roof Shingle Cost Underlayment for Gable Roof Nails for Gable Sheathing Roofing Nails for Gable Roof Rafters and Ties for Roof Rafters Length	Hip Roof Surface Area of Hip Roof Sheathing for Hip Roof Shingles for Hip Roof Roofing Nails for Hip Roof Cost of Shingles for Hip Roof Metal for Hip Roof Screws for Metal Hip Roof Purlins for Hip Roof Underlayment for Hip Roof Surface area for Double Hip Roof Hip Roof Geometries	Shed Roof Bundles of Shingles for Shed Roof Cost to Shingle a Shed Roof Underlayment and Cost for Shed Roof 4x8s for Shed Roof Metal Panels (Ag Panels) for Shed Roof Screws for Metal Panel Shed Roof Purlins for Shed Roof Trusses for Shed Roof Metal for Shed Roofed Animal Run-in
Dormers Surface Area of Dormers Metal for Dormers Screws for Metal Dormers 4x8s for Dormers Shingles for Dormers Roofing Nails for Dormers Purlins for Dormers	Pyramid Hip Roof Shingles for a Pyramid Roof 4x8 Sheathing for Pyramid Roof Underlayment for Pyramid Roof Metal Panels for Pyramid Roof Purlins for Pyramid Roof Pyramid Roof Geometries	Roofing Geometries Pitch to Slope Pitch to Angle Rise over Run to Angle Gambrel Angle Interface Angle Interface Angle from Rise over Run Trusses Needed for a Roof Area of Roof Section
Gambrel Roof Gambrel Roof Surface Area Gambrel Roof Shingles  Roofing Nails for Gambrel Roof Gambrel Roof Underlayment Purlins for Gambrel Roof Gambrel Roof Metal Panels Screw for Metal Gambrel Roof Gambrel Angle