How full should curtains be?
Fullness is the relationship between the width of flat fabric in a curtain and the width that curtain has to cover when it is closed. A curtain with more fabric across the same span has deeper, tighter folds. One with less lies flatter and shows more of the fabric's surface.
It is one of the few decisions that changes how curtains look without changing the fabric, the colour or the window. It is worth understanding before you order, because it is not something you can adjust afterwards.
What actually changes
Picture the same fabric made up two ways at the same window.
The fuller pair has folds that stand close together and hold their shape from the heading right down to the hem. Closed, it reads as a soft, substantial wall of fabric. Open, it stacks into a deep column at each side. The fabric's colour dominates and any pattern is broken up, because you only ever see part of the repeat at a time.
The flatter pair has wider, shallower folds that open out more. Closed, it looks lighter and more relaxed, and you see much more of the fabric itself. A large print or a woven texture stays readable rather than being folded away. Open, it takes up less room at the side of the window.
Neither is more correct. They are different looks, and they suit different fabrics and different rooms.
The heading sets the rhythm
Fullness and heading are not separate choices. The heading is what turns flat fabric into folds, and each type does it differently.
Pencil pleat gathers the fabric into a continuous row of narrow folds, so the fullness reads as an even, slightly informal texture across the top. Pinch pleat groups the fabric into fixed pleats at set intervals, which produces a more architectural rhythm and holds the folds in place down the drop. Eyelet curtains fold in deep, regular waves because the eyelets are set at fixed spacing. Wave headings are held at set intervals along the track or pole, which is why they hang in that consistent, even curve.
Each of those needs a different amount of fabric to look right, and the heading sets how much. Pencil pleat and pinch pleat, double or triple, are both made so the finished curtain width is 2.5 times the pole or track width. Wave is 2.2 times. Eyelet and tab top are 2 times, because the fixed spacing of the eyelets or the tabs already decides where each fold falls.
That is why the same cloth can look generous in one heading and slightly mean in another at the same window. The curtain headings guide covers what each heading looks like and how it hangs.
The fabric has a say
The same fullness looks different in different cloths, so the fabric choice comes into the conversation.
A heavy fabric, or one that has been lined and interlined, holds a broad fold and gains visual weight. Push the fullness too high and it can become bulky, particularly at the stack-back, where a lot of thick fabric has to sit at the side of the window.
A lightweight plain or a sheer needs generous fullness to look like anything at all. Sheers and voiles with too little fabric look thin and sparse, and every seam and hem shows.
Patterned fabric is its own case. A large repeat, a stripe or a strong print can disappear entirely into deep folds. If you have chosen a fabric for the pattern, a flatter curtain lets you keep seeing it. Browse the curtain fabrics with that in mind: how a fabric behaves when it is folded matters as much as how it looks flat on a sample.
Lining changes the picture too, because it adds body to a fabric that has little of its own. A lightweight cloth that would need a lot of fullness on its own can behave quite differently once it is lined. The curtain linings guide goes through what each lining does to the handle and the drape.
What the window and the room contribute
A small window with very full curtains can end up looking crowded, and the stacked curtains will cover a meaningful share of the glass. On a small window, or one where daylight is precious, a flatter curtain is often the practical answer as well as the better-looking one.
A tall or wide window carries fullness easily and generally benefits from it, because a flat curtain across a large span can look mean. Floor-length curtains on a big window are where generous fullness looks most at home.
Then there is the room's character. Deep, tightly gathered folds read as formal and traditional. Flatter, more open folds read as calmer and more contemporary. Wave and eyelet headings sit at the relaxed end for the same reason: their folds are wide and regular rather than dense.
More fabric is not automatically better
It is easy to assume that fullness is a quality signal and that more is always the safer choice. It is not.
Extra fullness means more fabric, so it costs more and it takes up more space when the curtains are open. It also puts more weight on the pole or track, which is worth remembering if the curtains are already heavy. And on the wrong fabric it simply looks wrong: over-gathered sheers look limp and over-gathered heavy weaves look lumpy.
The useful question is not "how full can these be" but "what do I want to be able to see, and how much room is there at the sides".
How this works when you order
With made-to-measure curtains you do not calculate the fabric width yourself. You give the measurements for the window and choose the heading and the fabric, and the workroom applies the fullness that heading is made at: 2.5 times the pole or track width for pencil pleat and for pinch pleat, 2.2 times for wave, 2 times for eyelet and tab top. On a 200cm pole that is 500cm of finished curtain width in pencil pleat and 400cm in eyelet, which is most of the reason the two stack so differently.
If you want something other than the standard for your heading, say so when you order. A different fullness can be made on a made-to-measure curtain, and it is a reasonable thing to ask for when the fabric or the space at the sides of the window argues for it. Your part of the decision is the look you want, not the arithmetic.
You can see how that works on the made-to-measure curtains. If you are torn between a fuller and a flatter finish, or between a heading and a fabric that want different things, the free design consultation is the quickest way to settle it. Fullness is much easier to judge with fabric in your hands than on a screen.