Measuring & fitting guides
Almost every blind that arrives wrong was measured wrong. Get these six rules right and you eliminate most of the errors — whether you're fitting it yourself or checking a fitter's work.
The six rules
In order. The first one decides everything that follows, which is why doing it second is how measurements go wrong.
Decide recess or face fix first
A recess fit sits inside the opening — neater, keeps the sill usable, suits deep reveals. A face fix mounts on the wall outside — bulkier, but covers far more and clears window handles. Rule of thumb: if you want it tidy, recess. If you want it to genuinely block light, face fix.
Measure in three places, every time
Window openings are not rectangles. For width, measure across the top, middle and bottom, and use the smallest. For drop, measure down the left, centre and right, and use the longest. Smallest width, longest drop — if you remember one thing, make it that.
Steel tape, millimetres
Not a fabric tape, which stretches. Record everything in millimetres, never centimetres and never inches. Irish suppliers manufacture in millimetres and converting a rounded figure adds error you cannot see until the blind arrives.
Make no deductions yourself
The supplier applies their own clearance deduction. If you subtract first, they subtract again and your blind is 20mm narrow. Give the exact opening size and write “exact recess size, no deductions made” on the order if you want to be certain.
For a face fix, be generous
Overhang the opening by at least 50mm each side, or 75–100mm each side for blackout. Allow 100mm above for a roller and 150–200mm for a roman, because a roman stacks to roughly a fifth of its drop. More overhang is almost never wrong.
Check what's in the way
Window handles that will foul closed slats, trickle vents at the top of the frame, alarm sensors in the corner of the reveal, tiled sills projecting into the opening, radiator shelves. Open and close the window fully with your hand where the blind will sit — if your knuckles hit, so will the blind.
What to write down
For every window, record: room name, window position, recess or face fix, width in millimetres, drop in millimetres, control side (left or right), and any obstructions. Photograph each window with the tape in place.
Send that to whoever is quoting. It removes half the back-and-forth and makes it possible to compare quotes on genuinely identical specifications — which is where the real savings are. On a full house, the spread between quotes for the same specification is routinely €200 to €400.
Tools you'll need
- Steel tape measure (not fabric)
- Pencil and a spirit level
- Cordless drill, 6mm and 7mm masonry bits
- Wall plugs matched to your wall type
- Screwdriver or driver bits
- Cable and pipe detector — don't skip this one
- Safety glasses
Step-by-step, by blind type
Every type page includes a full fitting sequence. Most fitting problems come from skipping the levelling step, not from the blind itself.
Fitting wooden blinds
6 steps · Warm, tactile slat blinds in real timber or faux wood.
Fitting day & night blinds
6 steps · Twin fabric layers of alternating stripes that slide to control light.
Fitting vertical blinds
6 steps · Rotating fabric louvres that stack to the side — built for wide windows.
Fitting venetian blinds
6 steps · Slim aluminium or metal slat blinds with precise light control.
Fitting roman blinds
6 steps · Soft fabric blinds that fold into horizontal pleats as they rise.
Fitting roller blinds
6 steps · A single sheet of fabric on a tube — the simplest and most versatile blind.
Fitting curtain poles
6 steps · Poles, tracks and finials — the hardware that makes curtains hang properly.
Fitting perfect fit blinds
6 steps · Clip-in frames that fit uPVC windows with no drilling at all.
Fitting roof & skylight blinds
6 steps · Tensioned blinds with side rails, made for sloped and roof glazing.
Fitting pleated blinds
6 steps · Concertina fabric blinds, including insulating honeycomb cells.
Fitting plantation shutters
6 steps · Hinged louvred panels fitted to the window — the most permanent option.
Fitting electric & smart blinds
6 steps · Motorised blinds on remote, app or timer control.
Measuring & fitting questions
Should I measure in millimetres or centimetres?
Millimetres. Irish and UK blind suppliers manufacture in millimetres, and rounding to the nearest centimetre introduces a 5mm error before you have even started.
Do I subtract anything for clearance?
No. Give the exact opening size. The supplier applies their own deduction — usually about 10mm on a roller — and if you deduct as well, the blind arrives 20mm narrow with daylight down both sides. This is the single most common and most expensive measuring mistake.
What is the difference between recess and face fix?
A recess fit sits inside the window opening and looks neater. A face fix mounts on the wall outside the opening, covers more, and blocks far more edge light. If you want it tidy, recess. If you want it to actually block light, face fix.
How do I measure a bay window?
As two, three or five separate windows. Measure each pane individually with its own three width readings and three drop readings, and note the angles between them. Never treat a bay as one measurement.
What tools do I need to fit a blind?
A steel tape, a pencil, a spirit level, a cordless drill with a 6mm or 7mm masonry bit, wall plugs suited to your wall, a screwdriver, and a cable and pipe detector. The detector is the one people skip and the one that prevents a very bad afternoon.
Can I fit blinds into plasterboard?
Yes, with proper metal anchors or spring toggles rated for the weight, or by finding the studs. Standard plastic plugs in plasterboard will pull out under a heavy blind or a lined curtain, usually a couple of weeks after fitting.
Get three quotes
Tell us about your windows once. Vetted local fitters come back to you with prices, usually within two working days. Free, and there's no obligation to book anything.
Start my free quoteBrowse the shop
Ready-made blinds, measuring tools, cord safety kits and fitting hardware — hand-picked and delivered to your door if you'd rather do it yourself.
Visit the shop