Start with the installed track or rod
Pinch pleat curtains need reliable finished measurements because the tailored heading is made to a specific width. Measure the full usable span of the installed hardware rather than the window opening alone.
Then measure from the correct hardware reference point to the floor. The calculator explains the reference point for track runners, rings and rods before you enter the value.
Do not add width or subtract floor clearance yourself
Choose your floor finish in the guided flow. The shared calculator engine converts your raw measurement into the recommended production size and carries it into the curtain selection step.