How a staircase is measured: total rise, going and step count
Written by Scott Jones, The Stair Guys, independent staircase measuring and sourcing specialists·Last updated
Understanding how a staircase is measured tells you what a good survey is checking, and why a figure typed into an online box is so easy to get wrong. The set-out itself is a short piece of arithmetic. The accuracy is all in the details around it.
The set-out, step by step
- Measure the total rise. This is the vertical height the stair has to climb, measured from the finished floor at the bottom to the finished floor at the top. Finished floor means with the coverings on, the tile, carpet, screed or boards, at both levels. Measure to bare subfloor and forget the finishes and every step will be the wrong height.
- Divide it into equal risers. Pick a number of risers so that the total rise divided by that number gives an equal rise per step within the limit (220mm maximum in England). For example, 2600mm over 13 risers is 200mm each. Too few risers makes each one too tall, so the rise per step sets the minimum number.
- Set the going. Choose the going, the depth of each step, so the stair is comfortable and legal: the pitch (the angle) at or below 42 degrees, and 2R plus G, twice the rise plus one going, between 550mm and 700mm. A 200mm rise with a 250mm going gives a 38.7 degree pitch and 2R plus G of 650mm.
- Check the rest. Confirm there is 2m of headroom the whole way, the width works, and any landing or turn lands where there is room for it. See a full worked example.
Why the details beat the arithmetic
The sum is easy. What goes wrong is everything around it. The finished floor levels are the classic one: allow for the flooring at one end and not the other and every riser is out, and the equal-rise rule means one wrong step throws the lot. Then there are the things a tape on a drawing never catches: walls that are not square or plumb, a floor that is not level, headroom that dies under the trimmer, an opening that is drawn tighter than it really is. That is the difference between a measurement and a survey, and it is why we measure the real space on site rather than build off a figure or a form. See why an online stair designer can get it wrong and why a plan can fail in reality.
Frequently asked
How do you measure for a staircase?+
Start with the total rise, the height from the finished floor at the bottom to the finished floor at the top, allowing for the floor coverings at both ends. Divide that by a whole number of risers to get an equal rise per step within the limit (220mm maximum in England), then set the going so the pitch stays at or below 42 degrees and 2R plus G is between 550mm and 700mm. Finally check headroom, width and any landing.
How do you work out the number of steps in a staircase?+
Divide the total rise by the maximum allowed rise per step and round up. For example, a 2600mm total rise divided by the 220mm England maximum is 11.8, so you need at least 12 risers, and 13 risers gives a comfortable 200mm rise each. The rise per step must be equal for every step, so the total rise sets the minimum number of risers.
What is the total rise of a staircase?+
The total rise is the full vertical height the staircase climbs, measured from the finished floor at the bottom to the finished floor at the top. Finished floor means with the coverings on at both levels. It is the starting figure for setting out a stair, and measuring it to bare subfloor instead of finished floor is a common and costly mistake.
Related guides
- Why an online stair designer can get it wrongAn online stair designer works from what you type in and quietly assumes square walls, allowed-for plaster and floor finishes, fine headroom, and that you know the regs. Here is what it misses, and why the final order should come off a site measure.
- Why a staircase that works on the plan can still fail in realityA flat plan cannot show headroom, buildability or the real millimetres. Here are the staircase mishaps a drawing hides, from headroom and door swings to winders, the wrong stair category and newel posts, and why a site survey catches them.
- How much space does a staircase need?A straight staircase for a normal storey needs roughly 2.6 to 3 metres of clear floor length for the flight, plus landing space at the top and bottom and the stairwell opening above. Where that run is not there, you turn the stair into an L or U shape, or use a spiral as a last resort. A staircase cannot be made shorter in the same footprint without becoming too steep to be legal.
- Are my stairs too steep, and can you make them less steep?Stairs feel too steep when the pitch is close to or over the 42 degree legal maximum, and they are often that way because the space forced it. The catch is that making a stair shallower needs more floor length, not less, so you cannot shallow it in the same footprint. To genuinely fix a steep stair you have to open up the space, moving a wall, door, the floor opening or joists.
Ready when you are.
Free and no obligation. The Stair Guys survey the real space, never off a plan.