Curtain Measuring Guide: How to Measure Width and Length
Not sure how to measure for curtains? This curtain measuring guide explains how to measure your window, rod or track, choose the correct curtain width and length, and avoid common sizing mistakes before ordering.
Accurate measurements help custom curtains cover the window correctly, hang at the intended length and provide the desired privacy and light control. Before measuring, decide whether you will use a curtain rod or track and choose your header style, as these choices determine where each measurement should begin.
If your hardware is already installed, measure the usable width of the rod or track. If it has not been installed, measure the window frame first and plan the final hardware position before calculating the curtain size.
How to Measure Curtains for Windows — Step by Step
Decide Where to Mount the Curtain Rod or Track
Most full-length curtains are installed outside the window frame on a wall- or ceiling-mounted rod or track. This can make the window appear taller and wider while improving light coverage.
Inside mounts are more common for blinds and shades, although they may also suit café curtains or certain door panels. Check the available mounting depth, handles and surrounding obstructions before choosing an inside mount.
Measure the Curtain Width
If a curtain rod or track is already installed, measure its usable hanging width. Do not include decorative finials in the measurement.
If no hardware is installed, measure the outside width of the window frame. Where wall space allows, plan for the rod or track to extend approximately 6–8 inches (15–20 cm) beyond each side. This provides better light coverage and gives open curtains room to stack beside the window.
Before ordering, check whether the product width refers to one panel, a pair of panels or the total finished coverage.
Measure the Curtain Length
Choose where you want the curtains to finish: above the floor, lightly touching the floor or pooling below it. Then measure from the attachment point required by your chosen header style.
For hook-mounted pleats, measure from the ring eyelet or hook attachment point. For grommet, tab-top, back-tab and rod-pocket styles, measure from the top of the rod. For ripple-fold curtains, measure from the carrier attachment point below the track.
For floor-length curtains, measure the drop at the left, center and right because floors and ceilings are not always level.
Double-Check Every Measurement
Measure every dimension at least twice. Repeat the width measurement, then repeat each length measurement before recording the final values.
Do not automatically add fullness until you confirm how the selected product defines its width. Some made-to-measure pleated and ripple-fold curtains already include the fabric needed to form their folds.
Still unsure? Use the Free Drapery Measurement Finder for product-specific guidance.
Inside Mount vs. Outside Mount: What’s the Difference?
Inside Mount
An inside mount fits within the window recess for a clean, built-in appearance. It is commonly used for blinds and shades and is less common for full-length curtains. Before choosing it, confirm that the recess provides enough mounting depth and clearance.
Outside Mount
An outside mount is installed above or beyond the window frame. It is the standard choice for most curtains because it can improve light coverage, create the appearance of a larger window and provide space for the fabric to stack when open.
Curtain Measuring Guide: Tips and Common Mistakes to Avoid
Allow Space Beyond the Window Frame
When planning new hardware, allow the rod or track to extend beyond both sides of the window where space permits. This can reduce light gaps and provide stack-back space. Treat this hardware extension separately from the fullness used to make the curtain folds.
Measure Both the Window and the Mounting Area
Record the window-frame width as well as the available wall or ceiling space for the rod or track. Check that brackets, finials and stacked curtains will fit without interfering with nearby walls or furniture.
Choose the Curtain Header Before Measuring the Final Length
Pinch pleat, grommet, rod-pocket and ripple-fold curtains use different attachment points. Select your curtain header style first, then measure from the correct starting point.
Check the Ceiling and Floor at Several Points
Measure the curtain drop at the left, center and right. Even a small difference in floor or ceiling level can affect how floor-length curtains hang.
Note Handles, Radiators and Other Obstructions
Window handles, deep sills, radiators, air vents, furniture and decorative trim can affect the curtain drop or prevent the panels from closing smoothly. Record these details before choosing the final size. If the window treatment uses an operating cord or continuous loop, keep it away from children’s furniture and follow the U.S. Consumer Product Safety Commission’s window-covering cord safety guidance.
Confirm Whether Fullness Is Already Included
Fullness requirements vary by header style. Some structured styles are ordered by finished coverage width, while soft-top styles may require additional panel width. Follow the instructions for the selected REGAL product rather than applying one multiplier to every curtain.
Use Our Curtain Measuring Tools
Ready to measure? Choose the tool that matches your window treatment. The Drapery Measurement Finder provides guidance for curtain width, length, header style and panel configuration, while the Blinds & Shades Measurement Finder covers product-specific inside- and outside-mount measurements.
Curtain Measuring Guide FAQs
Should I measure the window, curtain rod or track?
If the rod or track is already installed, measure its usable hanging width. If no hardware is installed, measure the window frame first, then plan the width and position of the new rod or track.
How much wider should a curtain rod be than the window?
It depends on the header style and how the product width is defined. Some pinch-pleat and ripple-fold curtains already include fullness during production, while rod-pocket, tab-top and other soft-top styles may require additional width. Always follow the ordering instructions for the selected product.
How do I measure curtain length for floor-to-ceiling windows?
Measure from the correct attachment point for the chosen header style to the desired finishing position. Take measurements at the left, center and right to check for an uneven floor or ceiling.
How do I measure curtains for a bay window?
The correct method depends on the hardware. Measure each section separately for individual rods or straight track sections. For a continuous bendable track, measure the planned track path and follow the track manufacturer’s instructions for corners and carriers.
Can I use the same measuring steps for blinds or shades?
No. Curtains are generally measured from a rod or track, while inside-mount blinds require precise recess width, height and mounting-depth measurements. Use the measurement tool created for the product you plan to order.
Correct curtain measurements improve coverage, operation and the finished appearance of your room. If you need help with a specific header, compare our Curtain Header Styles or use the Drapery Measurement Finder.
Ready to Find Your Perfect Fit?
Use our free curtain measuring guide and measurement tools to confirm your dimensions, then explore custom curtains made for your rod, track and preferred header style.
