How do I work out the number of steps?

Divide the total rise — finished floor to finished floor — by your target riser height, then round to a whole number. That whole number is your riser count. Dividing the total rise back by it gives the exact riser height, which is almost never a round figure, and that is fine: every riser being equal matters far more than the height being tidy.

What is a comfortable riser and tread?

A riser around 7 inches (about 178 mm) with a tread run around 10 to 11 inches (255 to 280 mm) walks comfortably for most people. Those are the defaults here, and you can change them. The old carpenter's check is 2 × riser + tread landing near 24 to 25 inches — a habit, not a rule. Building codes cap the maximum riser and set a minimum tread, so check your authority — this tool lays the stair out, it does not certify it.

Where exactly do I measure the total rise from?

From the surface people will walk on at the bottom to the surface they will walk on at the top — finished floor to finished floor. If the tile or the hardwood is not down yet, add its thickness on the side it is going. Subfloor to subfloor is only right when both floors get the same finish. Measure it plumb, in two places, with a level on the top floor if the floors are not parallel.

What does this tool tell me — and what does it not?

It gives you the riser count, the exact riser height, the tread count, the total run, the stringer length and the angle, all from your rise and your target dimensions, and it draws the profile. It does not size the stringer stock or tell you whether a board will carry the load. That is a structural question for your plans or an engineer, and it is deliberately out of scope.

How long does the stringer need to be?

The stringer is the hypotenuse of a right triangle whose legs are the total rise and the total run, so its length is the square root of rise squared plus run squared. That is the diagonal length of the cut line — the stock-length helper adds the extra you type for the plumb and level cuts and rounds up to the next board length.

How does the headroom check work?

It is geometry on three numbers you supply: how far the floor opening reaches back from the top riser, how thick the floor above is, and the minimum headroom your job requires. The nosing line drops one riser for every tread as it comes down, so at the header it has dropped opening length × (riser ÷ tread). Headroom is that drop minus the floor thickness. The tool compares it to the minimum you typed and, if it is short, says how much longer the opening needs to be.

Stair calculator

Altura total (de piso terminado a piso terminado)

Incluya el acabado de piso que todavía no ha colocado. Pulgadas, o pies y pulgadas como 9' 1".

Contrahuella objetivo

Lo que usted busca; la herramienta encuentra la contrahuella igual más cercana.

Huella (recorrido)

De cara a cara de contrahuella — no incluye el vuelo de la nariz.

Revisión de altura libre y tabla para zancas (opcional)

Hueco: de la contrahuella superior al cabezal

Horizontal, medido hacia atrás desde la cara de la contrahuella superior.

Espesor del piso de arriba

Altura de la vigueta + subpiso + acabado, en el cabezal.

Altura libre mínima que necesita

De sus planos o de su código — esta página no sugiere ninguna.

Tabla extra de zanca para los cortes

Cortes a plomo y a nivel, arriba y abajo; usted decide.

— contrahuellas

Guarde estos resultados

Enviamos este único correo a través de nuestro proveedor de correo y no guardamos su dirección.

Ver el procedimiento — con sus números

Before you type — how to measure

Total rise is finished floor to finished floor. If the top floor is getting 3/4 in hardwood that is not down yet, add 3/4 in to what the tape says (19 mm hardwood, add 19 mm). Subfloor to subfloor is only right when both floors get the same finish.
Measure plumb, not along a wall that might lean, and in two places — floors are rarely parallel. If they differ, use the rise at the stair and note the difference.
Tread run is riser face to riser face. The nosing hangs past that and does not count toward run; it is the bit your toe finds.
Read the tape as a number before you type: 9′ 1″ is 109 in, and you can type either form. A 9.1 is nine and a tenth inches — the tool will happily give you two risers. In metric, type the rise in millimetres: 2,769, not 2.769.

This lays out the geometry of a stair — spacing, count and lengths. It does not size the stringer or say whether a board will carry the load, and it does not replace the building code's riser, tread and headroom limits. Check all three before you cut.

Enter the total rise between the two finished floors and, if you like, your preferred riser and tread. The tool splits the rise into equal risers, gives you the exact riser height, then works out the total run and the stringer length from the right triangle the stair forms, and its pitch from riser ÷ tread — and draws it. Open the headroom fold to check the opening and to size the stringer stock.

The four words

Rise, run, nosing, stringer — every stair conversation uses them, and the first week they get mixed up. A riser is the vertical face; its height is the rise of one step. The tread is the flat part; its depth from riser face to riser face is the run. The nosing is the lip of the tread that overhangs the riser below — comfortable, but it is not run. The stringer is the sawtooth board the treads and risers sit on; its length is the diagonal.

Ejemplo resuelto

A total rise of 9 ft 1 in is 109 inches. Aiming for a 7-inch riser, 109 ÷ 7 = 15.6, which rounds to 16 risers. The exact riser is then 109 ÷ 16 = 6.81 in — 6 13/16 on the tape. Sixteen risers means 15 treads; at a 10.5-inch run that is a total run of 157.5 in. The stringer is √(109² + 157.5²) ≈ 191.5 in, and the stair pitches at about 33° (6.81 ÷ 10.5). The old comfort check, 2 × 6.81 + 10.5 = 24.1, sits inside the 24–25 that carpenters have aimed at for generations — a habit worth knowing, and not a code limit.

The same stair in metric: a 2,769 mm rise at a 178 mm target is 2,769 ÷ 178 = 15.6, so 16 risers of 2,769 ÷ 16 = 173 mm. Fifteen treads at a 267 mm going is a 4,005 mm total run, the stringer is √(2,769² + 4,005²) ≈ 4,869 mm, the pitch is 33° (173 ÷ 267), and 2 × 173 + 267 = 613 mm sits inside the metric 610–635 of the same habit.

Why 15 risers and 16 risers feel so different

Rounding the count is the only decision in a stair layout, and it changes every riser. On that 109 in rise, 15 risers would be 7.27 in each; 16 makes them 6.81. Half an inch a step, fifteen times, is the difference between a stair you notice and one you do not. In millimetres, 2,769 ÷ 15 = 185 mm against 173 mm for 16 — 12 mm a step. Try it.

Quick referencefor a stringer

Contrahuellas: total rise ÷ target riser, rounded to a whole number — then riser = rise ÷ that
Treads: risers − 1 (the top floor is the last tread)
Total run: treads × tread run — the nosing is extra on each tread, not extra run
Stringer: √(total rise² + total run²) · a 7 × 11 step is 13.04 in along the stringer, 32.5° off the floor (178 × 279 mm: 331 mm)
Stock: stringer length + your cut allowance, up to the next 2 ft — a 12 ft 9 in stringer wants 14 ft stock · metric, up to the next 0.3 m — 3.89 m wants 3.9 m
Métrico: 2,769 mm rise at a 178 mm target = 15.6 → 16 risers of 173 mm

Waste & overagewhat to add, and why

Stringer stock is bought long — the plumb and level cuts at each end need extra beyond the line length, and 2 ft steps in stock length mean a 16 ft stringer usually comes from an 18 ft board. Use the extra-stock field for your cuts.
Buy one more stringer than the plan shows; the first one is the pattern and sometimes the pattern is wrong.

Mistakes to catchbefore you order

Measuring the total rise from the subfloor when the top floor is getting ¾ in of finish that is not down yet — the tool's rise wants finished floor to finished floor.
Typing 9.1 for 9 ft 1 in; that is nine point one inches. Write 9' 1" or 109.
Counting the treads as the riser count; the tool solves risers, and treads are one fewer.

What an inspector looks forthe building inspector, at framing and again at final

On this part of the job

Every riser measured and every tread measured, then the largest compared with the smallest in the same flight. Uniformity is checked in its own right, separately from the size.
Rise, run, headroom and the width of the flight against the adopted code — look each one up, type it in here, and build to your own numbers.
Headroom measured from the nosing line, with the finished ceiling and the finished treads allowed for, not the bare stringer.
Nosing and tread projection, and that the finish you are adding later will not change either.
Guards and handrails: height, graspability, continuity, and how the posts are anchored into the framing rather than into the trim.
Stringer bearing top and bottom, and that cutting the stringer has not left too little timber behind the notch.

Have this ready

The total rise measured finished-floor to finished-floor, with every flooring build-up written down.
Your rise/run figures and the code limits you worked to, on paper.
A straight-edge long enough to span three nosings, and a level.

Every figure an inspector measures against comes from the code your jurisdiction has adopted, the stamped drawing, or the manufacturer's printed instructions — so none of them are printed here. Look the number up in your own book, type it into the tool, and the arithmetic is yours.

La fórmula

risers = round(total rise ÷ target riser) · stringer = √(rise² + run²)

Rounding the riser count and dividing back is what keeps every riser identical — the thing your feet notice on a stair. The stringer length is pure Pythagoras: the rise and the run are the two legs, the stringer is the hypotenuse. Headroom is the same triangle used backwards: the nosing line drops riser ÷ tread for every unit of horizontal distance, so at the header it has dropped opening × (riser ÷ tread), and the floor above takes its thickness out of that.

Preguntas

How do I work out the number of steps?: Divide the total rise — finished floor to finished floor — by your target riser height, then round to a whole number. That whole number is your riser count. Dividing the total rise back by it gives the exact riser height, which is almost never a round figure, and that is fine: every riser being equal matters far more than the height being tidy.
What is a comfortable riser and tread?: A riser around 7 inches (about 178 mm) with a tread run around 10 to 11 inches (255 to 280 mm) walks comfortably for most people. Those are the defaults here, and you can change them. The old carpenter's check is 2 × riser + tread landing near 24 to 25 inches — a habit, not a rule. Building codes cap the maximum riser and set a minimum tread, so check your authority — this tool lays the stair out, it does not certify it.
Where exactly do I measure the total rise from?: From the surface people will walk on at the bottom to the surface they will walk on at the top — finished floor to finished floor. If the tile or the hardwood is not down yet, add its thickness on the side it is going. Subfloor to subfloor is only right when both floors get the same finish. Measure it plumb, in two places, with a level on the top floor if the floors are not parallel.
What does this tool tell me — and what does it not?: It gives you the riser count, the exact riser height, the tread count, the total run, the stringer length and the angle, all from your rise and your target dimensions, and it draws the profile. It does not size the stringer stock or tell you whether a board will carry the load. That is a structural question for your plans or an engineer, and it is deliberately out of scope.
How long does the stringer need to be?: The stringer is the hypotenuse of a right triangle whose legs are the total rise and the total run, so its length is the square root of rise squared plus run squared. That is the diagonal length of the cut line — the stock-length helper adds the extra you type for the plumb and level cuts and rounds up to the next board length.
How does the headroom check work?: It is geometry on three numbers you supply: how far the floor opening reaches back from the top riser, how thick the floor above is, and the minimum headroom your job requires. The nosing line drops one riser for every tread as it comes down, so at the header it has dropped opening length × (riser ÷ tread). Headroom is that drop minus the floor thickness. The tool compares it to the minimum you typed and, if it is short, says how much longer the opening needs to be.

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