# Stair Calculator

> Determine the riser height, number of steps, and total run for a stair stringer. Add editable USD material and labor prices and compare low, middle and high budget scenarios.

Page: https://askcalculators.com/us/stair/
Definition: https://askcalculators.com/us/stair/definition.json
JSON Schema: https://askcalculators.com/us/stair/schema.json
Version: 20.13.0
Maintained by: AskCalculators (software project; not a credentialed reviewer)
Qualified review: pending. Automated checks do not establish professional approval.
Page status: Live
Review status: Pending

## Use
Open the calculator page and enter values. Query-string parameters can restore and bookmark a calculation.
Example: https://askcalculators.com/us/stair/?totalRise=108&targetRise=7&treadDepth=10&unitCost=30&laborCost=500&deliveryCost=30&costSpreadPercent=15

## Inputs
- unitSystem: Dimension units; type=select; optional; default=imperial; values=imperial|metric
- totalRise: Total rise (in / cm); type=number; optional; default=108
- targetRise: Target rise (in / cm); type=number; optional; default=7
- treadDepth: Tread going (in / cm); type=number; optional; default=10; min=0
- unitCost: Material price (USD / tread); type=money; optional; default=0; min=0
- laborCost: Total labor allowance (USD); type=money; optional; default=0; min=0
- deliveryCost: Delivery allowance (USD); type=money; optional; default=0; min=0
- costSpreadPercent: Low/high variation around entered subtotal (%); type=percent; optional; default=15; min=0; max=100

## Outputs
- numRisers: Risers; format=number; primary
- actualRise: Actual rise (in); format=number
- riseCentimetres: Actual rise (cm); format=number
- numTreads: Treads; format=number
- totalRun: Total run (in); format=number
- runMetres: Total run (m); format=number
- materialCost: Material cost; format=currency
- laborCost: Labor allowance; format=currency
- deliveryCost: Delivery allowance; format=currency
- unitRate: Entered USD rate / tread; format=currency
- estimatedTotal: Entered subtotal; format=currency
- costLow: Low budget scenario; format=currency
- costMid: Middle budget scenario; format=currency
- costHigh: High budget scenario; format=currency
- pricingStatus: Pricing status; format=text

## Formula
Riser count = rounded total rise ÷ target riser height; actual riser = total rise ÷ riser count; tread/run values follow the selected stair geometry.; material = unrounded purchase quantity × entered unit price; middle = material + labor + delivery; low/high = middle × (1 ∓ variation/100)

## Rules
- Empty optional inputs are undefined, not zero.
- Hidden conditional inputs are ignored.
- Do not invent missing required inputs.

Notice: Planning quantities and user-entered USD costs, not a contractor quote, structural design or code approval. Default prices are zero (unpriced); enter your supplier and labor quotes. New changes await independent review.