Stair rise and run layout

Stair Rise and Run Calculator

Turn total stair height into riser count, actual riser height, total run, and stair angle before moving into stringer, landing, tread, or handrail calculators.

Units

Total stair rise (ft)Target riser height (in)Tread depth (in)Waste / layout allowance (%)Rough cost per tread ($)

Riser count

Actual riser

Total run

Rough cost

Stair layout needs code checks

This calculator gives early stair layout math only. Maximum riser height, minimum tread depth, nosing, landings, headroom, handrails, guards, uniformity, and local code must be checked before cutting.

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Stair Stringer Calculator

Move from rise and run into stringer length and cut checks.

Stair Landing Calculator

Split a tall stair into flights around a landing.

Handrail Length Calculator

Estimate rail stock after the stair run is known.

View all

Stair rise and run formula

Riser count = ceiling(total rise ÷ target riser height)

Actual riser = total rise ÷ riser count

Total run = riser count × tread depth

Stair angle = atan(total rise ÷ total run)

Sample takeoff

A 9 ft total rise with a 7.5 in target riser and 10 in tread depth lays out 15 risers at 7.2 in actual rise, with about 12.5 ft of total run.A 2.7 m total rise with a 190 mm target riser and 255 mm tread depth lays out 15 risers at 180 mm actual rise, with about 3.8 m of total run.

Stair Rise and Run Calculator FAQ

How do I calculate stair rise and run?+

Divide total rise by your target riser height and round up to whole risers. Divide total rise by that riser count for the actual rise, then multiply risers by tread depth for run.Divide total rise by your target riser height and round up to whole risers. Divide total rise by that riser count for the actual rise, then multiply risers by tread depth for run.

Is total run always risers times tread depth?+

It is a quick planning convention. Some layouts count one fewer tread when the top floor acts as the last tread, so verify the exact framing detail before cutting.It is a quick planning convention. Some layouts count one fewer tread when the top floor acts as the last tread, so verify the exact framing detail before cutting.

When should I use the stair stringer calculator?+

Use this page for riser count and run. Use the stair stringer calculator when you need stringer line length, code checks, and cut layout.Use this page for riser count and run. Use the stair stringer calculator when you need stringer line length, code checks, and cut layout.