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Inch or
The main Navigation tabs at top of each page are Metric - inputs in millimeters (mm)
For Inch versions, directly under the main tab is a smaller 'Inch' tab for the Feet and Inch version.
by Image

Common Rafter Calculator - Rafter Dimensions - Plumb Cuts - Birds-mouth Dimensions and Cutting Templates - Metric

Rafter Run to Outer Wall
Roof Angle
Overhang (level)
Rafter Depth
Rafter Thick

Wall Thick
Wall Height
Allow for ridge thickness Allow for Ridge Thickness when determining Rafter Run to Outer Wall.

eg: Half building width minus 1/2 ridge thickness. See Rafter Run to Outer Wall Calculator below.

Print full scale Rafter Plumb Cut Templates and Birdsmouth Templates
Fold template over rafter to mark or cut through.

Angle Overhang

Rafter calculator angle dimension diagram
scale Use and Keyboard Keys to scale Birds-mouth. Birds-mouth

Rafter calculator dimension diagram

Open page with full scale printable birds-mouth cutting template at current rafter angle and dimensions.

Remember Ridge Thickness Remember to allow for Ridge Thickness in Rafter Run to Outer Wall.

Rafter Full Scale Profile Diagram

Calculate Rafter Run
to Outer Wall

Building Width
Ridge Thick
Rafter calculator ridge thickness adjustment diagram

DON'T BREATH THE DUST If you're cutting blocks, concrete, stone or ANYTHING and there's DUST - DON'T TAKE THE RISK
Don't cut it, or cut it wet so there's NO DUST - Silicosis Sucks
And if you're cutting wet, wear a mask - theres dust in the spray mist too!

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Create PDF to print diagrams on this page. Help Printing Help (new window)

Copy all diagrams on this page to bottom of page - Make multiple copies to Print or Compare.

View page on Phone via QR Code (Not current calculation result)

Zoom out to fit large full scale template images on screen - or to adjust scale to match ruler held against screen
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Zoom to adjust screen scale to actual size (measure full scale diagram with ruler) and hit 'Set' to set scale on other pages.

Click Slider to select then use keyboard cursor keys to fine tune.
Fine tune Sliders
Create and Print Full Scale PDFs with diagrams on this page (templates)

Copy all diagrams on this page to bottom of page - Make multiple copies to Print or Compare Results

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All calculators on this site are geometric only.
Check relevant local regulations for appropriate sizes, spacings and all engineering requirements.

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