Decide where the fabric should finish
Curtains can end at the sill, below it or near the floor. None of these choices is universally correct. A kitchen with a worktop below the window calls for a different decision from an unobstructed balcony door. First rehearse the movements around the window: opening it, airing the room, cleaning, walking past and perhaps pulling out a chair.
Fabric resting on the floor is a deliberate decorative choice that also adds work when cleaning. Where pets, frequently used doors or a narrow walking route are involved, a hem that stays clear may be more suitable. Make the decision for the occupied room rather than for a photograph in which nobody needs to move around.
Two windows with different conditions
Two windows in one room can look similar yet need different curtain lengths. One may sit above a radiator while the other has a desk in front. Do not force matching lengths purely for symmetry where that impairs use. Shared fabric or related mounting can connect the windows while each finishing height responds to its own conditions.
If a continuous visual line is important, consider whether another kind of covering suits one window better. A shorter working covering and decorative side panel can perform different functions. Each part still needs easy operation and must respect neighbouring appliance requirements.
Label measurements by window and side. Similar openings make figures easy to confuse. Record whether measuring took place before or after final mounting. A change to the pole can alter the hem position noticeably, and that may be difficult to correct neatly once the fabric is cut.
Measure from the actual hanging point
The starting point depends on the attachment. With rings, the top of the pole is not automatically the correct reference; with a track, neither is the ceiling. Establish the chosen system and its hooks first. Measure from the point where the fabric really hangs to the desired lower edge.
Take measurements at the left, centre and right. A floor may be slightly uneven, and a sill may slope. Record the differences rather than using only the most convenient figure. For two panels, decide whether they should appear equal in length or follow a real difference in the surface below. That choice becomes harder to change after cutting.
Consider care before the final hem
Read the care label and any stated allowance for changes in dimensions. If the manufacturer specifies washing before shortening, do that before making the permanent hem. Different fabrics require different treatment. A heavy fabric can also hang differently from the way it lies flat on a table.
A temporary stitched hem lets you see how the edge behaves. Leave the curtain hanging on its intended fittings and inspect it morning and evening. Draw it across and check whether the sides brush the floor during movement. One measurement of a stationary, open panel does not reveal the full movement of the fabric.
Check width at the same time
A curtain may have the right length yet fail to close properly because its width or mounting is unsuitable. Close both panels and inspect the middle and side edges. If they cover the window only when stretched completely flat, the appearance will differ noticeably from the gathered fabric seen while open.
Order after this combined check. Record the mounting system, starting point of the measurement, intended finishing height and care requirement. These details are more useful for sewing or reordering than a general request for floor-length curtains. They also let someone else understand exactly how the measurement was taken.
