Free tools for carpenters and joiners

Quick answers for the workshop and the merchant's counter, most of them worked out by the same code as JoinerKit's designer. Free, with nothing to sign up for.

• Sheet cutting calculatorType your parts and the sheet size, and see how many sheets of MDF or plywood to buy, each one drawn with every part on it, laid out for straight saw cuts.
• Timber cutting calculatorType the pieces you need and the lengths the timber comes in, and see which lengths to buy and what to cut from each, with the saw cuts allowed for.
• Stud wall calculatorType a wall's length and height, the stud centres and any doors or windows, and see the frame drawn, every stud, noggin and plate cut to length, and the timber to buy.
• Wall panelling calculatorShaker panelling, picture-frame moulding or tongue and groove: type the wall and the sizes, and see the panelling drawn, every piece cut to length and the timber to buy.
• Skirting and architrave calculatorType a room's walls and its doors, and see how many lengths of skirting and architrave to buy, with skirting stopping at each doorway and every architrave leg and head.
• Drawer box calculatorType a cupboard's inside width, height and depth and how many drawers, and get every front, box side, front, back and base cut size, with the runner length.
• Staircase calculatorType the floor-to-floor height and the going, and see how many risers, the rise, the pitch and the run, checked against Part K for a private stair, with the headroom hole.
• Shelf sag calculatorHow far an MDF, chipboard, plywood or timber shelf sags under books or ornaments, now and after a year or two, and the longest span that won't show a sag.