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About this tool
Frame timber running length and cft, shutter size and area, hinges and holdfasts for any door opening.
A door frame material calculator converts an opening size and a timber section into the running length of frame timber, its volume in cubic feet, the clear opening left inside and the shutter size once the rebate is allowed for. The running length is simply 2 × frame height + frame width for a three-sided frame, or plus a second width when a bottom sill is fitted; multiplying that by the section area gives the timber volume, and the clear opening is the outer size less one section width per side. It is written for carpenters, contractors and homeowners who need to order timber and hardware rather than guess.
Open Door Frame Material Calculator on AltFTool — it loads instantly in your browser.
Enter the values you already know.
Fine-tune the options to match your scenario.
Read the result and use it in your planning or reporting.
Timber merchants quote in running feet and in cubic feet — both are produced from the same section.
Clear opening and shutter size are worked out separately so the rebate is not forgotten.
Hinges scale with shutter height and holdfasts with the number of jambs, so the ironmongery list comes out too.
About 1.17 cubic feet for a 2100 × 900 mm frame in a 100 × 65 mm section. The running length is 2 × 2.1 + 0.9 = 5.1 m, and 5.1 × 0.100 × 0.065 = 0.0332 m³, which converts to 1.17 cft before any cutting wastage.
Add twice the frame height to the frame width for a three-sided frame, and add the width a second time if there is a bottom sill. A 2100 mm × 900 mm frame is 5.1 m of timber, which is 16.7 running feet.
About 724 × 2012 mm for a 900 × 2100 mm frame in a 100 mm section with a 12 mm rebate. The clear opening is 900 − 2 × 100 = 700 mm wide and 2100 − 100 = 2000 mm tall, and the shutter overlaps the rebate by 12 mm on each jamb and at the head.
Three butt hinges for a shutter up to about 2100 mm tall, and four above that or for heavy solid-core and fire-rated leaves. Space them roughly 150–200 mm from the top and bottom with the third centred, or follow the hinge manufacturer's load table when the shutter is unusually heavy.
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