How do I measure a Roman blind correctly?

First decide the mounting type – in the window recess (inside) or overlapping on wall/ceiling. Then measure width and height at several points and, for inside mounting, note the smallest measurement; for wall mounting, add an allowance on the sides and at the top.

Measure in the reveal or on the wall?

Both are possible. In the window recess, the Roman blind looks flush and discreet, but requires exact measurements minus a small tolerance. On wall or ceiling it covers the window, looks more generous and lets less side light through – here you add an allowance.

What allowance should I use for wall mounting?

For overlapping mounting, an allowance of a few centimetres on each side and enough space at the top for the fixing is recommended, so the window is well covered. The exact allowance depends on your situation – if in doubt, we measure on site.

Since a Roman blind is made to measure, the measurement decides the fit. If you're unsure, we come by in the Canton of Zurich for the free home consultation and measure your windows professionally.

Measuring a Roman Blind Correctly – Step by Step

Q: How do I measure for drill-free mounting?

Without drilling, the Roman blind is attached to the window sash with clamp brackets. What matters then is the sash measurement, not the wall opening: measure the width and height of the movable sash and make sure there is enough space for clamping.

MR Guide by Maiko Reiner · vinelly
Updated July 2026

Roman blind at the window – measuring correctly step by step

Step 1: Decide the mounting type

Before you measure, decide how the Roman blind should hang. Two options are available:

In the window recess (inside): The Roman blind sits flush in the window niche. It looks discreet and leaves the reveal free – but requires exact measurements minus a small tolerance.
On wall or ceiling (overlapping): The Roman blind covers the window generously, looks taller and lets less side light through. Here you add an allowance on the sides and at the top.

The mounting type determines all the following measurements – which is why it comes first.

Step 2: Measure the width

Measure the width at several points (top, middle, bottom), because windows are rarely perfectly right-angled.

In the reveal: Take the smallest measured dimension and subtract a small tolerance, so the blind doesn't jam anywhere.
On the wall: Measure the width to be covered and add an allowance of a few centimetres per side, so the window is well covered.

Step 3: Measure height / length

Measure the height from the planned top edge of the fixing to the desired lower end. In the reveal this is the niche height; for wall mounting you decide yourself how far the Roman blind should reach below the windowsill or to the floor. Here too: measure at several points and note it down.

Step 4: Consider the fold pattern and fabric length

When raised, a Roman blind falls into soft horizontal folds. When fully raised, the folded stack needs some build-up height at the top window edge – factor this in if a lintel, a handle or a tilt fitting is in the way up there. This way the window stays operable even with the blind fully raised.

Step 5: Without drilling = sash measurement

If you would like to mount without drilling it, the Roman blind gets attached using clamp brackets on the window sash in place. What matters then is the sash measurement, not the wall opening: measure the width and height of the movable sash and make sure enough space remains at the top edge of the sash for clamping. Ideal for rented flats, because no holes are needed.

Tips for measuring cleanly

How the professionals measure

Use a steel tape measure instead of a soft one – it doesn't stretch out of shape. Measure each measurement three times and note it down immediately. Always state the width first, then the height (width × height). For inside mounting, the smallest measurement. Don't round the value up or down yourself – note the exact value in centimetres.

Prefer we do it for you?

The general approach to measuring can also be found on our page Measuring correctly. And if you'd rather not take any risk: since a Roman blind is made to measure, we're happy to come to you in the Canton of Zurich for the free home consultation and measure your windows professionally.

Measurements ready? Continue now

Request a quotation – or we measure at your home free of charge in the Canton of Zurich.

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