How the order size is produced
A blind is rarely ordered at the raw measurement. An inside mount sits within the frame, so the adjustment is deducted at each side and from the drop; an outside mount covers the opening, so the adjustment is added instead. The side figure is entered once and applied to both sides. Slat count is the order drop divided by the slat spacing and rounded down, with the height below the last slat reported alongside it.
Take the adjustments and the slat spacing from the product manual or from whoever is making the blind. No standard is published here for either, because bracket and headrail designs differ too much to combine into one figure. Written as of October 2026.
This tool handles dimensions only. Curtain fullness ratios, light blocking and pricing are out of scope. Check your supplier's measuring rules before ordering.
Frequently Asked Questions
No standard deduction is published here. It varies with the product and bracket design, which is why the maker states it on the order form. Use the figure your supplier gives you.
An inside mount sits within the frame, so the measurement is reduced at the sides and in the drop; an outside mount covers the opening, so the measurement is increased. The mount type sets the direction, so enter adjustments as positive numbers.
It counts how many slats fit inside the order drop, so rounding down applies. The height left below the last slat is reported separately, and slat spacing comes from the product manual.