[{"data":1,"prerenderedAt":119},["ShallowReactive",2],{"pages:en":3,"type:en:spiral":89},{"home":4,"types":8},{"title":5,"description":6,"h1":7},"Free 3D Stair Calculator with DXF Drawings | StairGen Pro","Free stair calculator for 16 stair types: steel, wood, spiral and concrete. Rise, run, stringers, comfort and code check, live 3D and DXF for AutoCAD.","Stair Calculator with 3D Model and DXF Shop Drawings",{"metal-straight":9,"metal-straight-toothed":14,"metal-l":19,"metal-l-toothed":24,"metal-u":29,"metal-u-toothed":34,"spiral":39,"wood-straight":44,"wood-cut":49,"wood-l":54,"wood-l-winder":59,"wood-u":64,"wood-u-winder":69,"wood-three":74,"wood-three-winder":79,"concrete":84},{"slug":10,"title":11,"description":12,"h1":13},"steel-stair-calculator","Steel Stair Calculator: 3D Model & DXF Shop Drawings","Design a straight steel stair with stringer and tread brackets. Get rise, run, bracket spacing, cut list and fabrication drawings in DXF for AutoCAD.","Steel Stair Calculator with Fabrication Drawings",{"slug":15,"title":16,"description":17,"h1":18},"sawtooth-steel-stringer-stair-calculator","Sawtooth Steel Stringer Stair Calculator | 3D + DXF","Calculate a straight steel stair with sawtooth (cut) stringers: rise, run, stringer layout and plate cuts, with a live 3D model and DXF shop drawings.","Steel Stair Calculator with Sawtooth Stringers",{"slug":20,"title":21,"description":22,"h1":23},"l-shaped-steel-stair-calculator","L-Shaped Steel Stair Calculator with Landing | DXF","Quarter-turn steel stair with landing: split risers between flights, check comfort and slope, see it in 3D and download dimensioned DXF drawings.","L-Shaped Steel Stair Calculator with Landing",{"slug":25,"title":26,"description":27,"h1":28},"l-shaped-sawtooth-steel-stair-calculator","L-Shaped Steel Stair Calculator: Sawtooth Stringers","L-shaped steel stair with sawtooth stringers and a square landing. Rise, run, stringer cuts and bill of materials, with 3D view and DXF for AutoCAD.","L-Shaped Steel Stair with Sawtooth Stringers",{"slug":30,"title":31,"description":32,"h1":33},"u-shaped-steel-stair-calculator","U-Shaped Steel Stair Calculator | Switchback + DXF","Half-turn (switchback) steel stair with a full-width landing. Calculate both flights, check comfort and export fabrication drawings to DXF.","U-Shaped Steel Stair Calculator (Switchback)",{"slug":35,"title":36,"description":37,"h1":38},"u-shaped-sawtooth-steel-stair-calculator","U-Shaped Steel Stair Calculator: Sawtooth Stringers","Switchback steel stair with sawtooth stringers: flight split, landing size, stringer cuts and cut list, with live 3D and DXF shop drawings.","U-Shaped Steel Stair with Sawtooth Stringers",{"slug":40,"title":41,"description":42,"h1":43},"spiral-staircase-calculator","Spiral Staircase Calculator: 3D, Dimensions & DXF","Spiral stair calculator: number of steps, rise, tread angle and walkline going from height and diameter. Live 3D and DXF drawings, free.","Spiral Staircase Calculator",{"slug":45,"title":46,"description":47,"h1":48},"wooden-stair-calculator","Wooden Stair Calculator: Closed Stringer, 3D & DXF","Straight wooden stair with housed (closed) stringers: rise, run, stringer board width and length, comfort check, 3D model and DXF for AutoCAD.","Wooden Stair Calculator (Closed Stringers)",{"slug":50,"title":51,"description":52,"h1":53},"stair-stringer-calculator","Stair Stringer Calculator with Diagram | 3D + DXF","Cut stringer calculator: risers, treads, stringer length, board size and layout diagram from your total rise and run. Free, with 3D and DXF template.","Stair Stringer Calculator (Cut Stringers)",{"slug":55,"title":56,"description":57,"h1":58},"l-shaped-stair-calculator","L-Shaped Stair Calculator with Landing | 3D + DXF","Quarter-turn stair calculator: total rise split over two flights, landing size, stringer lengths and comfort check, with live 3D and DXF drawings.","L-Shaped Stair Calculator with Landing",{"slug":60,"title":61,"description":62,"h1":63},"winder-stair-calculator","Winder Stair Calculator: L-Shaped Kite Winders | 3D","Plan a quarter-turn winder stair: winder angles, tread going, stringers and comfort check. 3D model and DXF drawings.","Winder Stair Calculator (90° L-Shaped Winders)",{"slug":65,"title":66,"description":67,"h1":68},"u-shaped-stair-calculator","U-Shaped Stair Calculator with Landing | 3D + DXF","Half-turn (switchback) stair calculator: risers per flight, landing width, stringer lengths and stairwell size, with live 3D and DXF drawings.","U-Shaped Stair Calculator with Landing",{"slug":70,"title":71,"description":72,"h1":73},"u-shaped-winder-stair-calculator","U-Shaped Winder Stair Calculator (180° Turn) | 3D","Half-turn winder stair around a newel: winder angles, walkline going, stringers and comfort check, with a live 3D model and DXF shop drawings.","U-Shaped Winder Stair Calculator (180° Winders)",{"slug":75,"title":76,"description":77,"h1":78},"three-flight-stair-calculator","Three-Flight Stair Calculator with Two Landings | 3D","Three-flight (three-quarter turn) stair with two quarter landings: flight split, landing sizes, stringers and comfort check, in 3D and DXF.","Three-Flight Stair Calculator with Two Landings",{"slug":80,"title":81,"description":82,"h1":83},"double-winder-stair-calculator","Double Winder Staircase Calculator | 3D + DXF","Three-flight stair with two 90° winder turns: winder angles, walkline going, stringer lengths and comfort check, with 3D model and DXF drawings.","Double Winder Staircase Calculator",{"slug":85,"title":86,"description":87,"h1":88},"concrete-stair-calculator","Concrete Stair Calculator: Volume, Rebar & Landing","Concrete stair calculator with landing: steps, waist slab, concrete volume and rebar weight, plus a 3D model and DXF drawings. Free.","Concrete Stair Calculator with Landing",{"type":90},{"intro":91,"choose":94,"how":97,"norm":101,"faq":103,"related":116},[92,93],"This spiral staircase calculator lays out treads fanning around a steel centre column, with a helical handrail and balusters. Enter the floor-to-floor height (H), the outside diameter (D1), the column diameter (D2) and the total rotation (A), and it works out the number of steps, the riser height, the tread angle and the going on the walkline, then draws every tread so it can be cut.","A spiral is the stair that takes the least floor space (a {D1} mm circle with the default values) and also the easiest one to get wrong: too few treads and every step is a climb, too small a diameter and the usable tread disappears. Here you see it in figures and in 3D before anything is cut. The calculator works in millimetres or in inches (the mm / in switch in the editor), so it doubles as a metric spiral staircase calculator; the inch equivalents of the code limits are also listed below.",[95,96],"Choose a spiral staircase when nothing else fits: with the default values it sits inside a {D1} mm circle and climbs around a centre column. It is the classic secondary access (lofts, attics, roof terraces) and the most striking piece of metalwork, but not the most comfortable stair for carrying things up.","Unlike a stair with winders, it has no straight flights: all treads are identical wedges and the going grows from the inside out. For a comfortable stair, settle the diameter and the number of treads before the rotation: a small diameter leaves a narrow way through and too few treads give a high riser.",[98,99,100],"The height H = {Y} mm is divided between C = {C} treads: {riser} mm per step. The total rotation A = {A}° over the same treads gives {turn}° per tread. The going is not the same across the tread: it is measured on the walkline, where people actually walk, and there it is {going} mm. The calculator places the walkline 500 mm from the edge of the column.","Each tread is as long as the outer radius minus the column radius. Its outer width (the chord) and the width of the rough blank appear in the Data tab, so you can order plate or boards and nest the treads with little waste.","On a spiral the step formula tends to come out high: with the default values, 2 × {riser} + {going} = {step} mm (“{grade}”). The fix is more treads, that is, a lower riser; the Summary panel tells you how many. More rotation with the same number of treads widens each tread and lengthens the going.",[102],"Spiral stairs have their own rules. Under the IRC (R311.7.10.1), a spiral stair needs at least 26 in (660 mm) of clear width, a tread depth of at least 6¾ in (171 mm) at the walkline 12 in (305 mm) from the narrow edge, a riser of no more than 9½ in (241 mm) and 6 ft 6 in (1981 mm) of headroom. Australia's NCC sets a rise of 140–220 mm, a going of 210–370 mm and 2R + G between 590 and 680 mm for spiral stairs (check the current table before relying on it). In the UK, Approved Document K refers spiral and helical stairs to BS 5395-2. Note that the IRC and this calculator measure the walkline at different points: the going at 500 mm from the column edge only feeds the comfort check, so compare the going at 305 mm yourself when building to the IRC. On a spiral, the code check in the Summary compares only the riser, the width and the guarding, using the code's own spiral rules where it has them: under the IRC, 9½ in of riser and 26 in of width (R311.7.10.1); under the NCC, a rise of 140–220 mm.",[104,107,110,113],{"q":105,"a":106},"How many steps are in a spiral staircase?","As many as it takes to keep the riser within limits: divide the floor-to-floor height by the target riser and round up. For 2.8 m (about 110 in) and the IRC maximum of 9½ in that is 12 risers; for a more comfortable rise of around 200 mm it is 14.",{"q":108,"a":109},"What size spiral staircase do I need?","Kits usually range from about 1.2 to 1.8 m (4 to 6 ft) in diameter, and made-to-measure stairs go to 2 m or more. Under the IRC, 26 in of clear width plus the column and the handrail usually means a diameter of at least 5 ft (about 1520 mm). The smaller the diameter, the shorter the going on the walkline: change D1 and watch the going and the verdict.",{"q":111,"a":112},"How do you measure for a spiral staircase?","Measure the finished floor-to-floor height and the size of the floor opening, and decide where you want to step off at the top. The opening is usually a little larger than the stair diameter, and the rotation A sets where the top tread lands: 360° is a full turn and 450° a turn and a quarter.",{"q":114,"a":115},"Spiral or helical staircase?","The terms are often used interchangeably. Strictly, a helical stair turns around an open well with no column; the one in this calculator is a spiral staircase, with every tread fixed to a centre column.",[117,118],"metal-straight","wood-u-winder",1791467610718]