Staircase Calculator

UK Building Regulations (Approved Document K) set strict requirements for domestic staircases. The maximum rise per step is 220 mm and the minimum going (tread depth) is 220 mm. The pitch must not exceed 42°. Additionally, twice the rise plus the going (2R + G) should fall between 550 mm and 700 mm for comfortable use.

This calculator takes the total floor-to-floor height and available horizontal distance, then calculates the number of treads, individual rise, going and overall staircase length. It checks all results against Building Regulations and flags any dimension that falls outside permitted limits.

Headroom must be at least 2.0 m measured vertically from the pitch line. The calculator also shows the stairwell opening length required. For a standard floor-to-floor height of 2.6 m, most staircases need 12–13 risers and a horizontal run of approximately 3.0–3.5 m including a landing.

UK Building Regulations for staircases. Maximum pitch: 42° (residential). Maximum riser height: 220mm. Minimum tread depth: 220mm. Minimum head clearance: 2,000mm above pitch line. Handrail height: 900-1,100mm above pitch line. Balustrade gaps: under 100mm (child safety — should not allow 100mm sphere through). Minimum width: 800mm (some councils 900mm). Open risers permitted but with similar 100mm gap rule. Spiral staircase: separate rules, generally only secondary access.

Calculating staircase dimensions. Standard formula: rise + going = 550-700mm. Or: 2 × rise + going = 600-650mm (more accurate). Sample floor-to-floor 2,700mm (typical UK home): 14 risers at 192.8mm each. Goings (tread depths) at 220-250mm. Total horizontal run: 14 × 240 = 3,360mm. Required space: 3,360mm + landing space at top and bottom. New builds: standardised pre-built staircases £200-£800 from Magnet, Wickes, B&Q. Listed/older homes: custom carpentry.

Open vs closed riser staircases. Closed riser: traditional, conceals understair area, often used for storage. Open riser: modern, visually lighter, more open feel. Building regs require: 100mm sphere can't pass through (child safety). String stair: side stringers visible. Boxed/wall stair: side hidden. Cut stringer: treads visible on edge. Most UK homes: closed riser, boxed in. Modern: open tread, sometimes glass balustrade. Conservation areas: traditional designs typically required.

UK staircase costs 2026. Off-the-shelf softwood staircase: £200-£500 + installation £400-£800 = £600-£1,300. Mid-range oak: £800-£2,500 supplied + £500-£1,000 fitting. Bespoke hardwood: £3,000-£15,000+. Cutting costs: stairlift removal £150-£300; spindle replacement £15-£30 each; newel post £80-£200 each. Loft conversion staircase (steeper, often custom): typically £1,500-£4,000. Listed buildings: custom traditional carpentry £5,000-£20,000.

Common staircase issues. Squeaking treads: usually loose nails/screws to risers — re-screw from underneath, OR PVA glue between joints. Sagging: structural issue — may need stair surveyor; cost £80-£200 to assess. Worn carpet revealing splinters: sand and refinish (£100-£300) before recarpeting OR replace with hardwood/laminate. Newel post wobble: secure to floor joist or beam below. Loose balusters: dowel and glue, or replace. Stair gates for young children/pets: top and bottom — required to BS EN 1930:2011 standard.