Deck stair layout estimator

Deck Stair Calculator

Estimate deck stair steps, actual riser height, total run, stringer length, stringer count, tread pieces, waste, and rough material cost before laying out stringers. Use it as a field takeoff, then verify code before cutting.

Units

Total rise (ft)Target riser height (ft)Tread depth (ft)Stair width (ft)Stringer spacing (in)Tread boards per step Waste / extra layout (%)Cost per stringer ($)Cost per tread board ($)

Stringers to buy

Step layout

Stringer length

Rough cost

Deck stair layout is not code approval

This calculator estimates layout and material only. Stair code, maximum riser height, minimum tread depth, landings, handrails, guardrails, nosing, frost footings, stringer bearing, connectors, and local inspection rules must be checked before building.

Android App

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Stair Stringer Calculator

Dial in stair rise, run, and stringer geometry.

Stair Handrail Angle

Estimate the rail angle and diagonal length after the stair layout.

Deck Cost Calculator

Roll deck stair material into a larger deck price check.

View all

Deck stair formula

Steps = ceiling(total rise ÷ target riser height)

Actual riser = total rise ÷ steps

Total run = steps × tread depth

Stringer length = √(total rise² + total run²)

Sample takeoff

A 42 in total rise with a 7 in target riser and 10 in tread depth gives 6 steps, 7.0 in actual risers, about 5 ft of run, and a 6.1 ft stringer line before cut allowances.A 1.05 m total rise with a 175 mm target riser and 255 mm tread depth gives 6 steps, 175 mm actual risers, about 1.53 m of run, and a 1.85 m stringer line before cut allowances.

Deck Stair Calculator FAQ

How many deck stair stringers do I need?+

Divide the stair width by the allowed stringer spacing, round up, then add one outside stringer. This calculator also adds your waste percentage to the buy count.Divide the stair width by the allowed stringer spacing, round up, then add one outside stringer. This calculator also adds your waste percentage to the buy count.

Does this calculator check stair code?+

No. It gives layout math from the dimensions you enter. Verify riser limits, tread depth, landings, handrails, guards, connectors, and local code before cutting stringers.No. It gives layout math from the dimensions you enter. Verify riser limits, tread depth, landings, handrails, guards, connectors, and local code before cutting stringers.

Why does actual riser height change?+

The total rise rarely divides perfectly by your target riser. VibeCalc rounds the step count up, then divides total rise by that step count to show the actual riser.The total rise rarely divides perfectly by your target riser. VibeCalc rounds the step count up, then divides total rise by that step count to show the actual riser.