Stair Runner Length CalculatorUnit-specific calculation
Stair runner length calculator in inches
Inches are the working unit on site. Treads are rarely a clean 10 in, and a quarter inch missed on each of 15 steps is nearly four inches lost across the flight.
This calculator accepts inches as decimals (10.25) or as fractions (10 1/4, 10¼) and keeps the full precision through every step of the calculation.
Stair runner calculator
Your stair runner length
20 ft 3.1 in
Total runner required for 13 steps, including a 10% waste allowance.
| Inches | 243.1 in |
|---|---|
| Feet | 20.26 ft |
| Feet & inches | 20 ft 3.1 in |
| Yards | 6.75 yd |
| Meters | 6.17 m |
| Centimeters | 617.47 cm |
Recommended purchase length
21 ft
7 yd · 6.4 m · 252 in
This calculator provides an estimate based on the measurements and installation assumptions you enter. Complex, curved or winder staircases may require professional measurement.
Your measurements, drawn to scale
Why the inch total matters more than the foot total
Feet are for ordering; inches are for fitting. When you are marking out where each stair rod sits, or where a seam will fall, you need the inch figure. The tool shows both so you can order in feet and install in inches.
Entering fractional measurements
Type 10 1/4, 10.25 or 10¼ — all three parse to the same value. Mixed fractions with a space, plain fractions such as 3/8 and Unicode fraction characters are all handled, so you can copy figures straight off a tape measure.
A worked example in inches
15 steps, tread 10 3/8 in, riser 7 5/8 in. Each step consumes 18 in exactly, so the flight needs 270 in. A 1 in nosing allowance per step adds 15 in, taking it to 285 in. With 10% waste the order length is 313.5 in.
Questions people ask
- Can I enter fractions of an inch?
- Yes. The calculator accepts 10 1/4, 10.25 and 10¼ and treats them identically, so you can enter measurements exactly as you read them off the tape.
- How accurate does each measurement need to be?
- Work to the nearest eighth of an inch. Because every value is multiplied by the number of steps, small errors compound quickly across a full flight.