Straight Stair & Garden Step Calculator – Rise, Going & Layout

Plan a straight staircase or garden step layout

This free stair and garden step calculator turns a measured finished level difference into equal risers and horizontal goings. Enter the number of risers you want to investigate, or enter a target riser height and let the calculator find a nearby whole count. Then choose a going or fit the flight into a fixed horizontal run. The result includes a side elevation, nearby alternatives and setting-out coordinates.

The calculator is for one straight flight with the upper landing treated as the destination surface. It helps compare geometry before discussing the construction detail. It does not select structural members, design foundations, certify a staircase or replace checks for the applicable building and accessibility requirements.

Measure between finished levels

Total rise is the vertical difference between the finished lower surface and finished upper surface. Include the intended finishes when establishing those levels. Measuring from an unfinished slab at one end to finished paving at the other can create a different first or last rise after construction. Record the level references with the project name so the printed calculation remains understandable.

Horizontal run is measured in plan, not up the slope. In this calculator it extends from the first riser line to the last riser line. It excludes the space occupied by the lower approach and upper landing. If you only know the total available site length, allow for the separately designed landing and approach spaces before entering the flight run.

Risers and treads are not the same count

A flight with the upper floor or terrace as its destination has one fewer separate tread than risers. For example, six upward rises create five intervening tread surfaces before the upper landing. The calculator uses this convention consistently in run, surface area, pricing and the diagram. It does not silently add the upper landing as another purchased tread.

Riser count must be a whole number. The calculator divides the full rise by that count to make each rise equal. It retains precision internally; the displayed dimensions are rounded for reading. Do not multiply a rounded displayed riser height repeatedly to establish the upper level. Use the cumulative elevations in the schedule and verify the finished levels on site.

Exact count or target height

Exact-count mode is useful when checking a proposed design. Target mode divides the total rise by your desired riser height and rounds to a nearby whole count, with a minimum of two. It then recalculates the actual equal rise. A target is a preference, not a maximum allowable value, so rounding can produce a rise above the target.

The nearby-count table shows up to two lower and two higher counts. In fixed-going mode the going stays unchanged and the total run varies. In fixed-run mode the available run stays unchanged and the going varies. These alternatives make the tradeoff visible without choosing a supposedly universal best stair. Select the appropriate count in the inputs and recalculate when you want its full schedule.

Going, tread depth and pitch

Going is horizontal progress between adjacent tread noses. Physical tread depth may include a projection beyond that distance. Entering a projection in the optional area section increases the estimated tread surface area but does not change the going or pitch. Keep product depth and setting-out going distinct when using manufactured treads.

Pitch is calculated from an individual rise divided by an individual going. The diagonal from the bottom endpoint to the top endpoint uses the total level difference and total run; it is a different line because the flight has fewer goings than rises. The result labels that diagonal explicitly. It is not a stringer stock length, cutting length or support specification. End connections, bearing, thickness and construction details require separate treatment.

A simple worked example

For a 900 mm finished rise, six risers and a 300 mm going, each rise is 150 mm. There are five separate treads and the horizontal run is 1,500 mm. The pitch is approximately 26.565 degrees. The expression twice the rise plus the going equals 600 mm; the calculator reports it as a geometry value, without assuming a regional acceptance range.

If the flight is 1,000 mm wide and each physical tread projects 20 mm beyond its going, the five tread surfaces total 1.6 m². This excludes the upper and lower landings, vertical faces and waste. These dimensions are arithmetic examples, not a recommended design for every staircase or garden.

Optional comparisons against your own limits

Enable the comparison section when you have the project requirements. Enter minimum and maximum rise, minimum going and maximum pitch. Each candidate is marked as within or outside those entered values. No default regional limits are inserted and no green result should be read as a complete approval.

Other requirements can govern a usable staircase even when these four numbers fit. Headroom, landing dimensions, handrails, guarding, openings, slip resistance and accessible approaches are outside this arithmetic comparison. For work in England, consult the official Approved Document K publication and the other requirements relevant to the project. Its scope must not be assumed to cover every country or type of work.

Use the diagram and coordinate schedule together

The side elevation uses the same scale horizontally and vertically. It depicts the equal stair profile and a short highlighted upper landing marker. Tread projection, material thickness, drainage falls, foundations and supports are omitted. Long shallow layouts may look compressed vertically because the drawing preserves their proportions.

The optional schedule lists each riser line's horizontal distance from the first riser and its top elevation above the lower finished level. The final elevation equals the total rise. These are geometry references, not detailed fabrication marks for a specific stair system. Confirm how finished surfaces and construction layers relate to those references before transferring any marks.

Surface areas and optional costs

Tread area uses width times physical depth times the separate tread count. It does not calculate stepped concrete volume, excavation, stock-board cutting, riser coverings or landings. Use the related quantity calculators with a specified construction detail for those materials. One area figure cannot determine the volume of different possible stair foundations.

The cost section accepts a price per complete tread across the flight width and a price per complete riser. Enter zero for anything excluded. Add labour hours, hourly rate and other whole-job costs once. Markup adds to cost and tax applies afterward. Closing the tax details keeps the entered values; turning the cost checkbox off excludes the whole optional cost section while retaining entries.

The free print preview includes the diagram, alternatives, schedule and active options. It needs no email address or account. Use the separate Quote & Invoice Generator only if you want to turn a checked estimate into a customer document.

Stair and garden step FAQs

Why is there one fewer tread than risers?

The upper landing is the destination surface. Six rises therefore have five separate intervening treads in this calculator's convention.

Does target height enforce a maximum rise?

No. It selects a nearby whole count. Use your entered comparison limits and inspect the actual rise, or enter an exact count.

Can I fit the layout into a fixed run?

Yes. Choose fixed total run. It excludes landings and is divided by the separate tread count.

Is the diagonal a stringer cut length?

No. It is the endpoint-to-endpoint geometric diagonal only. Structural size, bearing and end details are not calculated.

Does it confirm building regulation compliance?

No. Optional checks compare four entered limits only. The full applicable design and construction requirements need separate review.

Can it calculate winding or curved stairs?

No. It models one straight flight. Intermediate landings and other flight shapes need a separate layout.

Can I print the result for free?

Yes. Calculate, open Print / Save PDF and use the print control. The coordinate schedule is expanded in the preview.

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