Stair Carpet Calculator
This stair carpet calculator helps you figure out exactly how much carpet you need to cover a flight of stairs. Enter the number of steps, riser height, tread run, stair width, and optional landing depth — and get the total carpet area instantly in square feet or square meters.
Stair carpet installation basics
Carpeting stairs follows the same procedure as carpeting a large floor area. We use the same materials and tools — hammers and nails, staplers, utility knives, and carpet knee kickers — to affix, cut, and position our carpet on the stair surface.
Installation can start from the lower floor going up, or from the top landing going down. For stairs with overhanging stair nosings, it is easier to install the carpet going up, as it is easier to tuck and staple the carpet underneath the nosing. On stairs without overhanging nosings, either direction works fine.
Besides the carpet itself, you may also need tack strips, underlayment, and optional double-sided adhesive tape. This calculator focuses solely on carpet quantity — area and cost.
How to use this stair carpet calculator
- Select your unit system — US Imperial (inches) or Metric (cm).
- Enter the number of steps (count every floor rise as one step).
- Enter the riser height — the vertical distance between two adjacent steps.
- Enter the effective tread run — the horizontal depth of each step from riser to riser.
- Enter the stair width — the distance between the walls on both sides, or the tread length.
- Optionally enter the landing depth if your staircase has a landing at the top or bottom.
- Optionally enter the carpet price per sq ft or m² and choose your currency to get a cost estimate.
- Click Calculate.
How to determine the size of stair carpet needed
The carpet for each step covers both the riser (the vertical face) and the tread (the horizontal surface you step on). The formula is:
Carpet area per step = (Riser height + Tread run) × Stair width Total carpet area = Number of steps × Carpet area per step + Landing area
For example, a staircase with 12 steps, a riser of 7 in, a tread run of 10 in, and a width of 36 in:
- Area per step = (7 + 10) × 36 = 612 sq in = 4.25 sq ft
- Total = 12 × 4.25 = 51 sq ft
It is advisable to add a 10–15% overage for cutting waste and pattern matching.
How to calculate the cost of stair carpet
Once you know the total carpet area, multiply it by the price per square foot (or m²):
Total cost = Total carpet area × Price per unit area
Our calculator does this automatically when you enter a price. You can choose from 20 world currencies including USD ($), RUB (₽), EUR (€), GBP (£), and more — making it easy to get a localized cost estimate wherever you are.
FAQs
What is a riser?
The riser is the vertical board between two steps — it is the height you lift your foot to climb each step. Standard risers are 6–8 inches (15–20 cm).
What is a tread run?
The tread run (or effective tread) is the horizontal depth of each step — how far your foot goes forward when you step. Standard treads are 9–11 inches (23–28 cm).
Should I include the nosing in my measurement?
The effective tread run is measured from riser to riser, which typically does not include an overhanging nosing. If your carpet wraps around the nosing, measure the actual carpet length along the tread surface instead.
Do I need extra carpet?
Yes. Always add 10–15% extra to account for cutting waste, pattern repeats, and future repairs. Our calculator gives you the theoretical minimum — always round up when purchasing.
What is a stair landing?
A stair landing is a flat platform at the top, bottom, or midpoint of a staircase. Enter its depth in the Landing depth field to include it in the total carpet area.