What Size Curtain Rod to Choose

Length: the measurement that matters most

The length of the rod is not calculated on the window, but around it. The rule: the width of the window plus an overhang of 15 cm on each side. In practice, the rod extends 30 cm beyond the frame in total. This overhang holds part of the curtain when it is pulled back to the side: without it, the open curtain hides more of the glass and darkens the room.

The calculation is simple: rod length = frame width + 2 times the overhang. For a 120 cm window, allow a rod of 150 cm. For a wide patio door, two curtain panels can meet in the centre, and the rod keeps the same 15 cm overhang at each end. To take your measurements, see the sizing guide.

Diameter: according to the weight of the curtain

The diameter of the rod is chosen according to the weight of the curtain and the width to span. The heavier and wider the curtain, the thicker the rod must be so it does not sag in the middle.

A dense, lined or technical curtain (thermal, blackout, soundproof) weighs far more than a sheer: it calls for a sturdy rod and brackets suited to its load, with none placed in the path of an eyelet or rod pocket curtain. For the details on load capacity and wall fixing according to weight, see which rod for a heavy curtain.

Projection: the distance to the wall

Projection is the distance between the wall and the rod. Allow 10 to 15 cm so the curtain falls freely without rubbing against the window sill, the handle or the radiator. Increase this distance if an obstacle sticks out: roller shutter box, protruding radiator, patio door handle. A projection that is too short presses the curtain against the obstacle and breaks the way it hangs.

Telescopic rod: practical but limited

The telescopic rod, which adjusts in length, is practical for small windows and light curtains. But it has a limit: over a wide span, it may sag under the weight of a heavy curtain. For a dense or technical curtain on a wide window, choose a rigid rod suited to its load, mounted on fixed brackets. The detail of the telescopic trap is in the guide to rods for heavy curtains.

Making your choice real: the made-to-measure curtain

The right rod is useless without a curtain at the right dimension, and vice versa. The width of the curtain follows from that of the rod, multiplied by 2 to 2.5 for the pleats (2.5 to 3 for the linen-effect light-filtering curtain); the height depends on the chosen heading and the desired hem level, and the sizing guide gives the reference point. Kurtens makes made-to-measure curtains to the dimensions you enter, in a range of colors and fabrics, delivered ready to hang. You enter the flat width of each panel and the height, and the curtain arrives at the right size. To also choose the type of fixing, see the fixings guide, then the Kurtens made-to-measure curtains.

What curtain rod diameter for a rod pocket or eyelet curtain?

Choose the diameter first for the weight of the curtain, then for its heading. For an eyelet curtain, Kurtens eyelets measure 40 mm: before ordering, check that they slide freely along the rod you have chosen. With a rod pocket, the rod must go in without forcing.

Eyelets and rod pockets thread straight onto a round rod: they do not fit on a track. The curtain slides along the rod itself, so a bracket in its path stops it. With two panels meeting in the centre, a central bracket is no obstacle: each panel stays on its own side.

The Kurtens rod pocket suits any fabric weight, but it slides less easily than eyelets: keep it for a curtain you rarely open. With heading tape, the supplied hooks attach to rings or to the gliders of a track: on a rod, check that the rings slide along it and that its load rating suits the bracket spacing; on a track, check the load rating of the system. For diameters by weight, see which rod for a heavy curtain.

How far from the wall or the window should a curtain rod or track be?

Leave enough gap between the wall and the rod or track for the curtain to hang without rubbing against the window, its handle or the radiator, and more if a roller shutter box sticks out. For a track, the gap must also let the pleats pass. At the sides, the rod extends 15 cm beyond the window on each side.

These two distances do different jobs. The gap from the wall lets the curtain hang without rubbing, and for a track, the manufacturer's instructions specify it; the side overhang moves part of the open curtain away from the glass. If the rod is not up yet, add these 30 cm to the width of the window: this gives the rod length, to multiply by 2 to 2.5 for the fabric width, or by 2.5 to 3 for the linen-effect light-filtering curtain.

In front of a door, the rule is the same: 15 cm on each side. Also check that the open curtain fully clears the doorway. In front of a window that opens inwards, check too that the sash does not hit the gathered curtain.

How much space does an open curtain take up?

When open, a curtain folds into a stack at the side. The width of that stack has no single value: it depends on the amount of fabric, its thickness and the heading. The 15 cm overhang on each side holds part of it; the rest may cover the edge of the glass.

The amount of fabric comes from the fullness: Kurtens recommends a curtain width of 2 to 2.5 times the rod length, and 2.5 to 3 times for the linen-effect light-filtering curtain. All of that width folds up. For two panels, divide it by two, then enter the flat width of each panel in the configurator: it applies no ratio.

With two panels that each open to their own side, the fabric is shared between both sides of the window instead of piling up on one.

Frequently asked questions

A well-sized rod holds the curtain and refines the way it hangs. Have your curtain made at the right size with Kurtens made-to-measure curtains, delivered ready to hang.