Stair rules for homes in Norway, Sweden, Denmark and Germany compared

Short answer: Of the four countries, only Norway and Germany set binding numbers for a stair inside a house. Norway’s TEK17 § 12-14 asks for a going of at least 250 mm, 0.80 m width (0.90 m if the stair turns) and 2.0 m headroom, with the step formula 2 risers + 1 going = 620 ± 20 mm. Germany’s DIN 18065 asks for risers of 140 to 200 mm, a going of 230 to 370 mm, 0.80 m width and 2.0 m headroom, with 2 risers + 1 going between 590 and 650 mm. Sweden’s rules since 1 July 2026 (BFS 2024:9) name no step measures, only 2.00 m headroom and 100 mm openings. Denmark’s BR18 has no requirements for a stair inside one home; its rules for shared stairs and Bolius’s 61 to 63 cm formula are the usual guide. One stair passes in all four: between floors 2.70 m apart, 15 risers of 180 mm and 14 goings of 260 mm, a stair 3.64 m long in plan, under a stairwell opening about 3.3 m long.

To work out your own stair, use the stair calculator and pick your country. It counts the steps, checks them against that country’s rules and gives the length of the stairwell opening.

The words used here

• Riser: the height from one step to the next (the rise of a step).
• Going: the depth of a step from one nosing to the next, seen from above. In the US it is often called the run or tread depth.
• Walking line: the line you walk along. In a straight stair it runs down the middle; in a spiral stair it is taken here halfway between the column and the outer edge.
• Headroom: the clear height measured straight up from the line through the nosings to whatever is lowest above you, such as the edge of the stairwell opening.
• Stairwell opening: the hole in the floor above that the stair goes up through.
• Guard: the railing that stops you falling off the side of the stair or into the opening. The handrail is the rail you hold.

The rules side by side

The table is for the main stair inside a single home, such as the stair between the ground floor and the first floor of a detached house. Rules as of November 2026.

What the table means in practice:

• Norway is the strictest on handrails (both sides) and on turning stairs, which must be 0.10 m wider than straight ones. DiBK accepts a stair that follows the step formula as meeting TEK17. Details in the Norwegian guide, Trapp i bolig: kravene i TEK17.
• Sweden replaced its building rules (BBR) on 1 July 2026. The new rule only says that people must be able to move safely on the stair; Boverket writes that it names no measures because each case needs its own risk assessment. The old advice is still a useful reference, and the calculator uses it. Details in Trappa i villan: Boverkets regler.
• Denmark regulates stairs in shared access routes, such as a stairwell in a block of flats, and leaves the stair inside a house to you. Bolius recommends using the shared-stair rules as a guide. Details in Trappe i huset: reglerne i BR18.
• Germany sets the most numbers, but allows the steepest stair: a 200 mm riser with a 230 mm going. Open stairs without risers need at least 30 mm of nosing overlap. A second stair that is not the required one may be 0.50 m wide. Details in Treppe im Einfamilienhaus: DIN 18065.

One stair that works in all four countries

1. Measure from floor to floor, from the finished floor below to the finished floor above.
2. Find the number of risers. Divide the height by about 180 mm and round to a whole number. The riser is the height divided by that number.
3. Choose the going from the step formula: going = 620 − 2 × riser.
4. Find the length in plan. A stair that ends on the upper floor has one going fewer than it has risers, so the length is (risers − 1) × going.

Example: The floors are 2.70 m apart. 2,700 ÷ 180 = 15 risers of exactly 180 mm. The going is 620 − 360 = 260 mm, so the stair has 14 goings and is 14 × 260 = 3,640 mm long in plan, at a pitch of about 35°.

That stair passes in every column of the table: 180 mm is within Germany’s 140–200 mm and Denmark’s 180 mm limit, 260 mm is above the 250 mm going of Norway, Denmark and the old Swedish advice, and 620 mm fits every version of the step formula. If the stair is open, without risers, add at least 30 mm of nosing overlap for Germany.

Where space is tight, the countries part ways. Germany allows a steeper stair: for the same 2.70 m, 14 risers of 192.9 mm with a 230 mm going (616 mm) make a stair only 2.99 m long. That is too steep for Norway, where the going must be at least 250 mm, and for the Danish and old Swedish guidance.

How long the stairwell opening must be

The opening must be long enough that the edge of the floor above never comes lower than the required headroom above the nosings. Count back from the top riser:

Opening length = (headroom + floor thickness) × going ÷ riser

The floor thickness is the whole build-up at the opening, from the top of the floor above to the underside of the ceiling below.

Example: With 2.0 m headroom, a 300 mm floor, a 260 mm going and a 180 mm riser, the opening is (2,000 + 300) × 260 ÷ 180 = 3,322 mm long. That covers Norway, Sweden and Germany. Aim for 2.10 m in Denmark if you follow the shared-stair rule, and the opening grows to 3,467 mm. The width of the opening is the width of the stair, and its open edges need a guard.

Spiral stairs

A spiral stair saves floor space, but as the only stair to bedrooms it has to meet the same rules as any other:

• Norway: at least 0.90 m from the column to the outer edge and a 250 mm going on the walking line, which takes a diameter of about 1.9 to 2.0 m.
• Germany: 0.80 m usable width and at least 230 mm going on the walking line, which takes about 1.8 m.
• Sweden: no measures, but with the old 0.25 m going as a reference you need about 2 m.
• Denmark: no rule for a stair inside a house, so a smaller spiral is allowed, though it is hard to carry a bed or a wardrobe up it.

Common spiral stairs of 1.4 to 1.6 m are too tight for the Norwegian and German rules. They suit a second stair or a loft that is not used as living space. The square opening for a spiral stair is usually about 10 cm larger than its diameter; check the measurements with the stair maker.

Do you need a permit for a new stairwell opening?

Cutting a new opening means cutting the joists or slab that carry the floor, and every country treats that as work on the structure. Whatever the paperwork, have an engineer design the trimmer that takes the load of the cut joists.

If the new stair leads to a loft you are turning into rooms, the loft conversion may need its own permit. The loft floor area calculator shows how much of a sloped-roof floor counts as floor area in each country.

Drawing the stair in House Madness

House Madness is our own product. The free stair calculator works out the steps, the stairwell opening and spiral stairs for the country you pick, including Norway, Sweden, Denmark and Germany. Use this stair in my drawing opens the app with the stair ready to place.

In the app you pick a stair from pictures: straight, with one to three turns, spiral, or alternating tread. The app checks the steps, width and headroom while you draw, and shows the stair in 3D, where you can walk up it. See the help article on stairs, or try it in the app. The check is an aid: the stair must still be designed and built to the rules, and a new opening needs an engineer.

In short

• Norway (TEK17): going at least 250 mm, step formula 620 ± 20 mm, width 0.80 m (0.90 m turning), headroom 2.0 m, handrails on both sides, guard 0.9 m.
• Sweden (BFS 2024:9): no step measures; 2.00 m headroom and 100 mm openings are binding, and the old 0.25 m going is the usual reference.
• Denmark (BR18): no rules for a stair inside one home; Bolius recommends 61–63 cm and the shared-stair limits of 180 mm riser and 250 mm going.
• Germany (DIN 18065): riser 140–200 mm, going 230–370 mm, step formula 590–650 mm, width 0.80 m, headroom 2.0 m.
• A stair that works everywhere: 180 mm risers and 260 mm goings, about 3.6 m long for 2.70 m between floors, under an opening of about 3.3 m.