Measuring thermal curtains correctly: planning width, length and overlap

A thermal curtain can only hang well and cover the window reliably if its width and length match the way it is hung. So don't just measure the glass: what matters is the track or rod, the overlap you want at the sides, and how the fabric will gather.

Before measuring: check the hanging method and product details

First decide whether the curtain will hang on a track, a curtain rod or another system. The measuring points differ depending on the hanging method. Also check in the product description whether the stated width refers to one panel or the whole set, and whether hooks, eyelets or heading tape are provided.

Finding the right width

With an existing track, measure its usable length; with a rod, go by the distance the curtain actually needs to cover. If the fabric should extend beyond the window frame, add the overlap you want on both sides. This keeps the edges better covered when the curtain is closed.

Then allow for fullness: curtain fabric does not lie flat but forms folds. The fabric width you need therefore depends on the folds you want, the hanging method and the manufacturer's information. With two panels, the total width is split between both sides; always compare the total with the width stated for the set.

Measuring the length from hanging point to hem

Measure from the point where the fabric is hung to the desired end point. For floor-length curtains, a hem just above the floor usually looks neat and is easier to clean. If the fabric should rest on the floor, take that into account deliberately in the target length. Check the measurement at several points if the floor or ceiling is not quite level.

Allow for radiators, windowsills and walkways

If there is a radiator under the window, the curtain should not unnecessarily block its air circulation. Choose a suitable length or make sure the fabric can be pulled aside while the heating is on. Also check whether window handles, deep windowsills, furniture or doors affect how the curtain hangs and opens.

Measuring checklist before ordering

• Decide on the hanging method and measuring point
• Note the usable track or rod width
• Plan side overlap on the left and right
• For several panels, check the width stated for the whole set
• Measure the length to the desired hem at several points
• Take radiators, windowsills, handles and furniture into account

When measurements and hanging method match, the thermal curtain is easier to fit and hangs more evenly. Compare the specific product dimensions and the manufacturer's notes once more before buying.

For made-to-measure curtains, you enter your measurements directly on the product page – our checklist for made-to-measure curtains shows which details you need. Suitable models are in made-to-measure thermal curtains; check colour and fabric in advance with the sample book. Want to fit it without drilling? Read thermal curtains in a rented flat.