How to Measure for Curtains? Comprehensive Guide

Well-fitted curtains can make all the difference in transforming a room, adding a sense of balance and elegance. But even minor measurement errors can result in curtains being too short, too narrow, or not properly placed. Most people don’t realize how easy it is to measure curtains accurately.

In this blog post, you will find out how to accurately measure the width and length of your curtains, the best mounting height, how to determine the proper fullness, and what size mistakes to avoid. Measuring for curtains can be tough, but with the step-by-step instructions and examples, you can do it with confidence and have beautiful curtains from the start.

Curtains work hard in the background of any space. They determine the light and dark levels, provide privacy, dampen sound, and affect the character of warmth or coolness of a room. See a window as something that’s more than just glass. The opening is part of a wall, and the whole area is covered with curtains. If the dimensions are correct, the fabric will hang in even folds and will frame a room. If it is incorrect, they look awful.

There are some problems that arise from poor measurements.

1. Curtains are too short and resemble the shrinkage of a pair of trousers. These are too tight and have gaps where the light can get through. Or they are not full or drawn in when closed. With a careful start, each issue can be easily avoided.
2. The other one is the cost angle. Ready-made panels can be returned, but custom curtains are cut to your exact figures. With made-to-measure work, the number you give is the number you get. That is why slowing down at the measuring stage saves both money and frustration later.

Once the stakes are set, it’s easy to take the next step: collect the proper tools before you get your hands on the window.

The most essential tool around is a steel tape measure. Fabric tapes sag and stretch over long drops, and even a little stretch will off-center your figures. A hard metal tape will provide the same measure each time.

In addition to the tape, there are some that are close by:

• A step ladder or sturdy stool, so you won’t have to lean or guess to reach the top of the window
• A pencil and a piece of paper on which to draw and write each figure as it is drawn
• Two people to hold the tape on the large windows

Because curtain sizes are almost always given in the order “width first, height second,” record your measurements that way. Write whether you are working in centimeters or inches, and use only one of these measurements.

Always measure your window twice. In most buildings, windows are not perfectly square, particularly in older buildings. Repeating each figure two or three times reveals small errors, which are not costly.

A kit is complete once all components are assembled; then you can follow a logical sequence as you go through the measuring process.

It all reduces to two fundamental numbers. The width of your curtains and the length they must hang. All else follows these. It’s also important to take into account the order. Determine the position for your rod or track next, since the hardware position is what will affect the size of the curtain, not the glass itself.

If you haven’t yet attached your rod or track, use a strip of masking tape or a pencil to mark where you’ll attach it to the wall. From that mark, you can determine accurate measurements. We have broken down the process below into width, height, and the two mounting options you will have to choose from.

1. Measuring Window Width

Begin with the width of the rod or track, rather than the window itself. This is the number that determines the quantity of fabric that is required.

Take the length of the rod from one end to the other. Of course, the decorative finials on the ends should not be included – curtains don’t cover those. If the rod is not up yet, determine the distance that it should extend beyond the window.

A rod always needs to stick out of the frame on both sides. This allows the drapes to slide up the wall when extended, instead of piling against the window. Generally, make the rod 15 – 25 cm (6 – 10 inches) longer than the window. To achieve a bigger view, or to allow in the maximum amount of light, try to make the side length up to 30 cm (12 inches).

A worked example is given below. Suppose that your window frame is 120 cm wide (47 inches wide). If you add 20 cm (8 inches) to each side, your rod will be 160 cm (63 inches) long. This is the length of the rod you bring into the calculation of the fullness later.

2. Measuring Window Height

The height is also commonly referred to as the drop, and is the distance from the rod (or track) to the intended curtain length. Again, this is not because of the position of the top of the glass, but because of the rod’s position.

Before mounting the rod, determine the height of the rod mount. The recommended height is 10-15cm (4-6 inches) above the window frame. Elevated, placed nearer to the ceiling, pulls the eye upwards and makes the room appear taller. The rod is placed 15 to 30 cm (6 to 12 inches) above the frame in a high-ceilinged room to achieve this effect.

After measuring the height of the rod, take a measurement straight down to the desired destination. Repeat this reading on the left and right sides of the window. There are no always level floors and ceilings, and even if there is a centimeter difference, it may show when the fabric hangs.

For example, if you want your curtains to just touch the floor, and your rod is 145 cm (57 inches) high above the floor, your curtains will end up about 144 cm (56.5 inches) long. The placement of the curtains is discussed in the length section below.

3. Measuring for Inside Mount Curtains

Inside mount refers to curtains that are hung within the window recess, the rod or track mounted inside the recess, not on the outside of the wall. This is an appropriate style for deep window recesses and provides a built-in appearance. It’s a frequent occurrence in apartment window sets with a window located within a window reveal.

To measure for an inside mount, find the width inside the recess. Measure at the top, middle, and bottom; recesses may be a bit off. Use the smallest of the three figures so that the rod fits without forcing.

To determine the drop from the top of the recess to the bottom of the recess or to any point within the recess where the curtains should finish. Inside-mount curtains often end just at the sill, keeping the fabric contained.

Remember, the inside mount does not allow for fullness, as this is a hard limit on width. Also, it does not obstruct the amount of light reaching the wall, as it is not overlapping. That’s why blackout curtains are more effective when used as an exterior installation.

4. Measuring for Outside Mount Curtains

The most common mount is an outside mount. The rod or track is attached to the wall over and around the window, and the curtains span the entire window area. This way, you have complete control of width, height, and light control.

Determine the position of the rod as described above:

• Extend it past the frame on both sides,
• Position it above the top of the frame.

Now drop the rod from the height to the floor or wherever you want it to go. When blocking light out completely, enlarging a window, or concealing an undesirable window frame, an outside mounting is the superior solution. It also allows you to let the curtains roll away from the glass when open. The most flexible method is used for most curtains that reach the floor.

Once you understand the basic approach, you should consider how changes to the rooms will affect your needs.

The measuring method stays the same from room to room. What changes is the goal. A bedroom needs darkness. A dining room leans toward style. An office needs glare control. Matching the curtain choice to the room makes your measurements more useful.

Living Room Curtains

Floor-length curtains are a great option in living rooms as they are generally used to make a statement. In this instance, height can be a positive. Lifting the rod high and allowing the curtains to reach the floor helps to open up the area.

Also, make sure to aim for a big width. Large, even folds are generally needed for living room windows, since they tend to be the biggest in the house. If your living room has sliding doors or a long open area, you might need a track instead of a rod and possibly more than two panels. Use the full opening your baby will need, add some side extensions, and cut the fabric across the panels, making it easy to draw.

Bedroom Curtains

Light control is the most important factor in bedrooms, which are all about rest. Blackout curtains come into the picture. An outside mount will work best for dark areas, the rod will be extended far past the frame, and high up on the mount.

Take additional measurements for the middle seam overlap at the centre where two panels join, and the return seam at the sides, where the cloth folds back to the wall. The overlaps prevent light from seeping through gaps. For a blackout setup, add approximately 5-10 cm (2-4 inches) of overlap in the middle.

Generally, the floor-length option is chosen when it comes to the bedrooms because it is a choice that not only looks good, but will also help to block out the light at the bottom edge.

Dining Room Curtains

Eating areas tend to be more about ambiance and design. Curtains in this area might be more decorative, and fullness and fabric will go with it. Longer panels are better for more formal dining rooms, shorter panels are better for more informal.

Measure the same way as you would for any exterior mounting but pay a little more attention to the fullness. The softer, layered folds are achieved with a richer gather, which is a rod width or more.

Office Curtains

The challenge at home offices is to control the glare on the screen without darkening the room. Light filtering or sheer curtains are usually the best choice – sometimes with a heavier curtain.

If you want both privacy in the daytime and glare control in the night, then plan for layers when measuring for an office project. Typically, this requires a double track or a rod and another sheer track. Determine the length of each layer, ensuring that each layer is even with the preceding layer, and extending the layers away from the wall to let the front layer overlap the back layer.

The two factors that determine the final order of the room the most are length and width. The first thing we’ll examine is length.

The length determines the ambiance of a window. The same panel that looks formal at the end can look casual or careless at the end. There are four endpoints to select from.

The first is the length of the sills. The curtain is stopped just at or approx 1 cm above the windowsill. This informal style is appropriate for kitchen spaces, small windows, and areas where furniture is placed below the window.

The second one is the tapron length. A few centimeters below the bottom of the window sill, the curtain ends. It is a neat and functional choice for numerous rooms.

The third, and most popular for bedrooms and living rooms, is the floor length. The curtain either barely reaches the ground or is held about 1cm above it. This is a neat, straight, easy-to-open, and easy-to-close hanging piece!

The fourth is the puddle. The fabric dangles several centimeters to the ground and pools to give a soft and dramatic effect. It is elegant, but dusty, and is not suited for curtains used every day.

Standard ready-made drops are often sold at fixed sizes such as 137, 160, 183, 229, and 274 cm (54, 63, 72, 90, and 108 inches). If it seems to be in the middle of two sizes, take the larger size and hem to fit. With custom curtains, however, this is not an issue as they are created to your specific drop. Once you’ve determined the length, you need to determine the width.

Most people make their mistake in the width. It’s a natural instinct to pull the curtain down to the window. In reality, curtains need far more fabric than the window is wide, or they pull flat when closed and look thin.

It is not the width of the glass but the width of your rod or track that is important. Multiply this width by a fullness ratio to get the required fabric width. The ratios are explained in the next section, but the rule of thumb is: 2 times your rod width or more in fabric for most fabrics.

Here’s an obvious illustration. Your rod is 160cm (63in) long.

If you want a standard, full curtain, multiply by 2, which will result in 320cm (126inches) of total curtain width. For two panels, both panels must be 160 cm (63 inches) wide. When closed, this pair will completely dress the window, and when open, will stack up neatly.

Use a pair of panels? Keep in mind, each side will need half of the fabric. If you want a lighter, more modern appearance, then you can go down to 1.5 times the rod width. Sheer fabrics, on the other hand, will generally look best when they are two to three times the width; they need volume to be considered full. As it is all driven by fullness, let’s take a closer look at it.

The ratio of the fullness represents the amount of curtain fabric on one rod or track. It is the only idea that gives flat fabric a touch of elegance.

2x means that your fabric will be twice as wide as the rod. Most curtains use standard, and it provides a nice, balanced, gathered appearance. A ratio of 1.5x will create a more subtle and understated wave pattern. If the ratio is 2.5x or higher, then it produces a deep and rich drape, like a hotel!

The correct ratio is dependent upon the fabric and the heading. Fabrics such as velvet, which are heavy, require less fullness, such as 1.5x. Light fabrics or sheers require more, in many instances 2x to 3x.

The style of the heading is also important. There are fullnesses in some headings. Pinch pleat and pleated headings are sewn with the pleats already in place, so the panel will not be as wide as it appears when flat. Wave or ripple-fold curtains that hang in even, smooth S-shaped folds are designed to hang on a special track with evenly spaced gliders, and the fullness is determined by the spacing of the gliders, not by you adding extra width.

However, for eyelet and rod-pocket headings, you can choose the fullness by the amount of fabric you order, the more fabric you order, the fuller the hand.

With this information, you will be able to determine whether pre-made curtain sizes are suitable or custom curtains are more appropriate.

Two choices for curtains are ready-made curtains with set widths and drops, or those that are made to size. They are faster and more economical, and work well with normal windows. The compromise is fit. You need to fit one of the window sizes in the set, or you’ll have to deal with a bit of bunching, a small window gap, or a hem job.

Typical panels are usually sold by the panel, with the assumption being that a pair of panels will cover a window half the width of the combined width of the panels when fullness is accounted for. When purchasing ready-made, always check the flat width and drop, round up, not down.

They are made to your dimensions: Custom (or Made to Measure) Curtains. You select the width, the drop, the heading, the lining, and the fabric. The outcome is a perfect fit, and there is no room for guesswork involved. This will be the preferred path for unusual window shapes, very wide spans, very deep recesses, and when you wish to have a certain type of pleat, such as a wave pleat or pinch pleat.

Custom curtains are clearly the best option for blackout performance. Unlike most off-the-shelf panels, you can construct in the center overlap and side returns that will tighten the light. The same applies to tall windows, in which case the usual drop just falls out.

To sum up, ready-made suits are for average windows and the budget, whereas tailored suits are for a perfect fit and special requirements. Regardless of your option, a few professional habits will enhance your outcomes.

The same few lessons keep cropping up after I’ve installed curtains in numerous homes. It’s these little habits that make a huge difference.

The first thing to do is to always put the rod or track into place before you order custom curtains anywhere. The distance from the real position of the hardware eliminates any guesswork and provides the actual drop.

Second, take the measurements of each window individually. Often, there is a difference of a centimeter or two between two identical-looking windows. Look at each opening individually.

Thirdly, take into consideration the return and the overlap. Return is the length of the curtain from the front of the rod to the wall. Overlap is the area of overlap between two panels. Both are important for coverage and light control, and both can easily be overlooked.

Fourth, inspect for obstructions. Curtains will be influenced by door handles, window cranks, radiators, and skirting boards. Always keep your rod extended enough off the wall to keep it from touching. Particularly with large headings.

Fifth, round up, don’t down. If a figure is between two sizes, use the larger size. If the curtain is slightly too short, you can always hem it, but if it is too short, you can’t add fabric.

Lastly, document it and preserve it. Record the width of the rod, the drop on each side, the heading, and the fullness that you selected. If you reorder or add a matching window at any point, then that record will save time. Most common questions are answered by these habits, but here are some that do arise frequently.

Even the careful fall into the same snares. The easiest way to avoid them is to know them ahead of time.

What’s commonly made is measuring the window, not the rod. The glass provides little information about the fabric to be used. It’s the width and position of the rod that matter.

The second most common mistake is to hang the rod too low and too narrow. A rod mounted just above the frame and the same width as the glass makes the window appear tiny and allows open curtains to obscure the view. Assemble higher and higher.

Another very common mistake is neglecting to watch for fullness. The panels are not pulled flat when closed, and are purchased exactly the same width as the rod. Always have extra fabric on hand.

Individuals also fail to take measurements on both sides of the drop. Single measurements can make one side too long due to sloping floors and dipping ceilings. Take both.

Finally, many don’t remember the heading allowance. The length of a rod-pocket or eyelet panel is slightly shortened at the top, where it wraps around the rod; the end product will be lower than the flat panel indicates. Take that into account before ordering. The majority of measurement mistakes can be avoided by avoiding these five.

Curtains can be easily measured. It only pays for care. Begin with the rod, not the glass! Make up measurements on both sides of the curtain to determine its width and then sketch the curtain’s end where you want it to stop. Consider fullness in the fabric so that it drapes in soft folds, and match the style with the room and its function.

Repeat each figure twice, record it and round up if necessary. Do so, and your curtains will fit snugly, you can control the light flowing through as you please, and you’ll frame each window according to its worth. You can use pre-made curtains or custom-made panels and the process is the same, which results in the same satisfying window look: like it was meant to be that way.