Measure the space the curtain has to cover, not just the window. That means the full track length, including the wall either side where the curtain stacks when it is open, and the drop from the top of the track or rod down to where the hem should finish.
Decide where the track goes first
Every other number hangs off the track position, so settle that before the tape comes out. A curtain can be fixed to the ceiling, to the wall above the window, or inside a recess, and each one changes both the width and the drop.
Ceiling fixing gives the tallest, cleanest look and stops light and warm air spilling over the top. A face fixed track on the wall usually sits around 100mm to 150mm above the architrave, high enough to clear the frame and low enough to stay off the cornice.
Look at what is above the window before you decide. A bulkhead, a split system, a downlight or a deep cornice can make the decision for you.
Width is the opening plus the stack
Measure the window from the outside edge of the architrave on one side to the outside edge on the other. That is almost never the finished track length.
A curtain pulled open has to park somewhere. If the track stops at the frame, the stacked fabric sits over the glass and you lose a slice of light and view every day.
Run the track past the frame so the stack lands on the wall instead. Then measure how much clear wall you really have beside the window, out to the nearest corner, cupboard, light switch or power point, because that is your limit.
How much room the stack needs
Stack back is the width a curtain takes up when it is fully open. It depends on the heading, the fabric weight, the lining and the fullness, so no single figure suits every curtain.
The old rule of thumb for a lined, pleated curtain is that the stack takes around a third of the track. S fold packs tighter than that, and a light sheer tighter again. The S fold and pinch pleat comparison explains the difference.
Decide early whether it opens as a pair or draws one way. A pair splits the stack across both sides, while a one way curtain needs all of that room on one side, often the better setup beside a sliding door.
Drop: where to measure from
On a track, measure the drop from the top of the track down to the floor. If the track is going on the ceiling, measure from the ceiling itself.
On a rod with rings, take it from the bottom of the ring where the curtain hooks on, not from the top of the rod. For eyelet curtains, measure from the top of the rod, because the fabric above each eyelet sits over it.
Measure the drop at both ends and in the middle. Floors and ceilings in older Sydney houses are rarely level, and a curtain made to one figure can show a gap at one end and drag at the other. Work to the shortest of the three so the hem clears everywhere, and write everything in millimetres.
Choosing the finished length
Most floor length curtains finish about 10mm to 15mm off the floor. That clears carpet and floorboards, stays out of the way of the vacuum, and still looks like it reaches the ground.
A puddled curtain is made long on purpose so the fabric pools on the floor. It looks soft in a formal room. In a busy one it collects dust, gets trodden on and ends up looking tired.
Sill length curtains finish just below the sill and suit a window over a bench, a bed head or a heater. Floor length holds warm air against the glass far better on a cold night, which the sheer and blockout curtain guide covers in more detail.
Check what the curtain has to clear
Look for anything that sticks out. Window winders, door handles, a deep sill, chunky skirting boards and a pelmet that is staying put all change how far the track has to sit off the wall.
Sliding doors are the usual trap. The handle sticks out further than people expect, and a track fixed too close catches the curtain on it every time it is drawn.
If a blind is going in as well, measure for both at once. A face fixed roller blind behind the curtain needs room for its roll, so the curtain track has to sit far enough off the wall to clear it.
Fullness is ordered, not measured
You do not measure fullness at the window. You measure the track, and the fabric width is worked out from that, usually at 2.0 to 2.5 times the track length so the curtain still has folds in it when it is closed.
This is where home measuring goes wrong most often. Someone measures the window, buys a curtain the same width, and ends up with a flat sheet of fabric that will not close properly.
The made to measure curtains we supply and install are sized from the track length and the heading, so that sum is done before anything is cut.
Your own measurements tell you whether the curtain you have in mind will fit the wall. For the order itself, Steve comes out and measures it himself, checking what the track can fix into and where the stack will sit. Book a free measure and quote and you will see where the track would go before anything is ordered.
Common questions
How far past the window should a curtain track go?
Far enough that the curtain stacks on the wall rather than over the glass. A heavy lined pinch pleat needs more room than an S fold sheer, and a corner or a cupboard beside the window sets the limit.
How high above the window should curtains be hung?
A face fixed track usually sits around 100mm to 150mm above the architrave. Going higher, or fixing the track to the ceiling, makes the window look taller and cuts the light and draught coming over the top.
Should curtains touch the floor?
Most are made to finish 10mm to 15mm off the floor so they hang straight and clear the floor covering. A curtain that drags picks up dust and wears along the hem. Puddling is a deliberate style for a room that does not see much traffic.
Do I measure the window or the track for curtain width?
The track. The curtain is then made at around 2.0 to 2.5 times the track length so it still has proper folds when closed.
How do I measure the drop for curtains on a rod?
For curtains hanging from rings, measure from the bottom of the ring to the floor. For eyelet curtains, measure from the top of the rod. Check the drop at both ends and the middle and work to the shortest figure.