Dimensions and profiles
Comfort checks
Usual comfort and safety values, not legal requirements. Check the rules that apply to your building.
The staircase in your room
Which shape fits?
| Shape | Space needed (mm) | In your room | Weight | Action |
|---|
Cut list
| Part | Profile | Length (mm) | Qty | kg each | kg total |
|---|
Bars to buy
| Profile | Metres used | Pieces | Bars | Waste | kg used | kg bought |
|---|
How it is calculated
- The straight staircase runs from the lower floor to the upper floor. The number of risers is the height to climb divided by the desired riser height, rounded; the actual riser height is the total height divided by that number.
- The treads are the risers minus one on each flight: the last one is the upper floor or the landing. The tread depth comes from the formula 2h + g = 630 mm (with 0 in the depth field) or you enter it.
- The stringer follows the line of the treads: the length is measured on the upper edge, as number of treads × √(h² + g²). The ends are cut at the angle shown (horizontal at the bottom, vertical at the top); add an allowance for fixing plates.
- The L- or U-shaped staircase has a landing between two flights. The risers are split between the flights (flight 1 has the ones you choose, or half of the total if you enter 0), and each flight must have at least 2. The landing of the L is square (the width of the stair); the one of the U has the width of two flights plus the gap between them and the chosen depth (at least the width of the stair).
- The landing has a tube frame (two sides along the depth, three across the width, with a cross member in the middle), legs in the number chosen and plate or another material. The landing railing follows the open sides: for the L the two outer ones, for the U the far side, the two short sides and the gap between the flights (with a single railing, only the far side).
- Each tread sits on cross members between the stringers, as long as the stair width minus the stringer widths (with a single stringer, the stair width). A plate tread has the stair width and the tread depth plus the nosing.
- The railing has posts at no more than the chosen spacing, measured along the slope, vertical balusters at the chosen clear gap and the handrail along the length of the stringer. Posts and balusters have the railing height plus the fixing below the tread, minus the thickness of the handrail.
- The room: the staircase is placed in the chosen corner, turned by 90° if that makes it fit; the space needed is the area taken by the flights and the landing. Doors, windows, columns and the access space at the ends are not taken into account.
- The opening in the floor: it is made along the last flight, from the point where a person of the chosen headroom would touch the slab (the thickness of the slab is subtracted from the total height) to the edge of the upper floor; the width is the width of the stair.
- The weight and the surface to paint include the stringers, cross members, landing, railing and, if you choose plate, the treads and the landing (both faces). Treads in another material are not included in the weight.
- Bars are filled simply: longest pieces first, with the blade thickness between them. The cutting program usually finds a better arrangement.
- The weight uses the chosen material (carbon steel, 7.85 g/cm³, by default) and the same formulas as the weight calculator, with the rounded corners of the tubes (EN 10219).
- For each profile you can choose “Custom profile”, with your own dimensions (square or rectangular tube, round or square bar, flat bar), and the material can be anything, with your own density.
A quantity estimate, not a strength calculation. The calculator does not check the strength of the stringers, landing, treads, connections or fixings and does not account for the rules of your building (for example for railings, outdoor or escape stairs). For outdoor stairs, great heights or public spaces, ask a specialist for a calculation. The comfort checks use usual values, not legal requirements. The plan in the room does not account for doors, windows or columns; also check the headroom on site.
Frequently asked questions
How is the number of steps chosen?
The calculator divides the height to climb by the desired riser height (175 mm by default), rounds to the nearest whole number and recalculates the exact height. For an L- or U-shaped staircase, the risers are split between the two flights (half, or as many as you enter for flight 1).
What is the 2h + g formula?
It is the stride rule: twice the riser height plus the tread depth should come to about 630 mm (comfortable between 600 and 640 mm). The calculator uses it to find the tread depth when you enter 0 and checks it in the “Comfort checks”.
How do I choose between a straight, an L and a U staircase?
It depends on your room. The straight staircase is the simplest but needs the most length. The L-shaped one takes a corner, and the U-shaped one folds into the width of two flights. The “Which shape fits?” table compares them for your room: the space needed, whether it fits and the weight.
How does the room check work?
You enter the length and width of the room and the corner where the staircase goes. The calculator places the staircase in that corner, turns it by 90° if that makes it fit and draws the plan. It tells you how much space is left or how much is missing and how large the opening in the floor must be, so that you have the chosen headroom (2000 mm by default) above the treads.
How is the stringer cut?
The length shown is on the upper edge. The ends are cut at the angles in the results: the first is the angle to the axis of the piece for the horizontal cut (at the floor or the landing), the second for the vertical cut (at the upper floor). Measure on site and add what you need for the fixing plates.
What does the calculator not include?
Curved, spiral and winder staircases, fixing plates, bolts, welding, painting and labour. The lengths are theoretical and this is not a strength check. The spiral staircase is planned as a next step.
How do I import the list into the cutting program?
Download the CSV file and import it into the cutting program (step 1). The pieces appear with square ends (90°); you enter the stringer angles in the program from the values in the results.