AbraCalc

Low-Angle Outdoor Stairs — 48 Inch Rise, 12 Inch Treads

Gentle outdoor stairs spanning a 48-inch rise with deep 12-inch treads need about 7 comfortable steps.

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How to use this tool

  1. Measure the total rise from the lower finished floor to the upper finished floor.
  2. Enter a comfortable target riser height (about 7-7.75 in).
  3. Enter the tread depth (run per step), at least 10 in for most codes.
  4. Read the riser count and the exact riser height to cut.
  5. Confirm the total run fits your available floor space.

Design comfortable low-angle outdoor stairs with extra-deep treads for safe exterior access.

Frequently asked questions

How many stairs do I need for a given height?
Divide the total floor-to-floor rise by a comfortable riser height (about 7.5 in) and round to the nearest whole number. A standard 108-inch rise gives 14 risers and 13 treads.
What is a comfortable riser height?
Around 7 to 7.75 inches. Most codes cap risers at about 7.75 inches, and a common comfort rule is that two risers plus one tread should total 24-25 inches.
Why is there one fewer tread than riser?
The upper floor acts as the final landing, so the top riser steps onto the floor instead of onto a tread. A flight therefore always has one more riser than tread.