Measuring guide
How to measure for roman blinds
Decide first whether the blind fits inside the window recess or outside it on the wall. Everything else follows from that choice.
Inside or outside the recess?
Inside the recess is the neater fit: the blind sits within the window reveal, the sill stays usable and it suits a deep recess with square corners. Outside the recess covers the whole opening, blocks more light, hides an uneven reveal and is the only option where the recess is shallow or has handles, vents or a sloping head in the way.
Check the recess depth
An inside fit needs enough depth for the headrail and the folded blind to sit clear of the glass and any handles or opening vents. If the recess is shallower than about 75mm, or a handle projects into the space, fit outside.
Measuring for an inside-recess fit
Width: measure in three places
Measure the width of the recess at the top, in the middle and at the bottom. Give us the smallest figure. Recesses are rarely square, and a blind made to the widest point will jam.
We make a small deduction from your figure so the blind runs freely inside the recess; don't take anything off yourself.
Drop: recess top to sill
Measure from the top of the recess to the sill, again in two or three places, and give us the smallest. The blind will be made to finish just clear of the sill.
Note anything in the way
Window handles, trickle vents, tiles or a sill that projects into the recess. A photo is the quickest way to show us; we can move the batten forward or advise an outside fit.
Measuring for an outside-recess fit
Width: recess plus 150mm
Measure the width of the recess and add 150mm — 75mm each side. That is the finished blind width. It covers the opening with a modest overlap onto the wall without looking oversized, and it is what we make to unless you ask for more.
Drop: from the batten to the finish point
The batten fixes 100mm above the recess. Measure from that line down to where the blind should finish, normally 100mm below the sill so the blind clears it. If the sill projects, the blind will sit against the sill rather than over it; tell us and we can add a spacer or make to the sill instead.
Check there is wall to fix to
You need 100mm of flat wall above the recess for the batten and 75mm either side. Coving, a picture rail, a neighbouring window or a boxed pipe can all get in the way. If they do, tell us what room there is and we size the blind to suit.
Controls and child safety
Roman blinds are operated by a chain or cord on one side. Note which side you want the control on, viewed from inside the room, and how high the control should finish. In any building where children may be present, the control must comply with BS EN 13120; we supply chain-break connectors and cord tensioners as standard and size them from the drop you give us.
What to write down
- Room / window reference
- Your own reference for the schedule and the blind label.
- Fit
- Inside or outside the recess.
- Width
- Inside: smallest of three recess widths. Outside: recess width + 150mm. In mm.
- Drop
- Inside: recess top to sill (smallest). Outside: batten line to finish point. In mm.
- Control
- Left or right (from inside), chain or cord, and finished control height.
- Lining
- Standard, dimout or blackout. Blackout still lets a little light past the edges of an inside fit; use outside fit for bedrooms that need dark.
- Obstructions
- Handles, vents, sills, coving, radiators below. Photo if in doubt.
Rather we measured?
For larger projects we can measure on site. Site surveys carry a fee that depends on the location, the number of windows and the stage of the build; we confirm it before anything is booked. Site surveys and installation.
Frequently asked questions
You say 75mm a side. Other guides say more.
Many domestic guides suggest 100mm or more, which suits a lightweight blind on a small window. On contract work 75mm a side reads as fitted rather than oversized, keeps the blind within its fixing and leaves room for a curtain track beside it. If you want the blind wider, just tell us the finished width you want.
Can I have a roman blind and curtains on the same window?
Yes, and it is common in hotel bedrooms. Fit the blind inside the recess and the curtains outside on a track sized from the curtains guide; measure each as if the other were not there.
Does the fold size affect the measurement?
No. We set the fold spacing from the drop so the blind stacks evenly. The three roman blind constructions on the specification page (standard, scalloped and shaped) all measure the same way.
Roman blinds are priced as part of a project quote
Send the blind sizes with the curtain fabric you have chosen and we price blinds, curtains and pelmets together in the same cloth.