How to measure for blinds. The right way.
Made-to-measure means exactly that. Give us the wrong number and the blind will not fit. Give us the right number and it will be perfect. This guide takes five minutes per window and covers every blind type we sell.
How do I measure windows for made-to-measure blinds in South Africa?
- Always measure in millimetres. Never centimetres, never a phone app. A 5mm rounding error creates a visible gap or a blind that will not fit the recess.
- For recess fit (inside the frame): measure width at three points and record the smallest. Measure height at three points and record the longest.
- For face fix (on the wall above the window): measure the area you want covered and add 50mm overlap on each side for full light block.
- Never make your own deductions. Give us the exact measurement. Our factory applies the correct clearance for each blind type.
- Measure every window individually, even if they look the same. South African homes settle over time and frames shift.
- Not sure? WhatsApp Duncan on 076 022 8410. Send a photo of your window and he will talk you through it.
Measure your windows then order online with instant quoting and free delivery, or WhatsApp for help.
Three golden rules
Break any of these and the blind will not fit correctly. Follow all three and it will be perfect.
Never centimetres. Never a phone app. A 5mm rounding error is invisible on a ruler but creates a visible gap at the edge of a blind. Your tape measure reads mm. Use that number.
Give us the exact measurement. Our factory knows exactly how much to deduct for each bracket type, each blind system. If you subtract your own clearance, the blind arrives too small.
Even windows that look identical. Garden Route homes, old and new, settle and shift. Frame sizes vary by builder and by era. Measure each opening individually, every time.
Step 1: recess fit or face fix?
This is the first decision and it changes how you measure. Look at your window and decide which option suits it before you take a single measurement.
Recess fit (inside mount)
The blind sits inside the window frame. Clean, built-in look. The frame acts as a border around the blind.
Best for: modern homes, minimalist interiors, windows with a deep enough recess.
Check before choosing: measure the depth from the front of the frame to the glass. There must be enough room for the headrail of the blind type you want (see recess depth table below). Also check for window handles, burglar bars, or anything else sitting inside the recess that the blind would hit when lowered.
Face fix (outside mount)
The blind mounts on the wall above the window frame. It covers the frame and overlaps on each side.
Best for: shallow frames, maximum light block, covering imperfections around the frame, or when handles or fittings block the recess.
Check before choosing: make sure the wall surface above the window is flat, solid, and suitable for drilling bracket screws into. Plasterboard walls need hollow wall anchors.
Step 2: how to measure
Recess fit measuring
Measuring inside the frame
You are measuring the internal opening: the space between the inner edges of the frame on all four sides.
Take three width readings (top, middle, bottom) and record the smallest. Take three height readings (left, centre, right) and record the longest. This accounts for frames that are not perfectly square.
Recess fit: what to record
Face fix measuring
Measuring outside the frame
You are deciding how much of the wall you want the blind to cover. You choose the size. The blind will be made exactly to the dimensions you give us.
For face fix, measure the total width you want covered including the overlaps on each side. Add at least 50mm on each side of the window frame for light block. For full blackout, add 75 to 100mm per side.
Face fix: what to record
By product type: what is different
The width and height method above applies to all blind types. But some products have specific measuring notes that matter.
Roller, zebra, and double roller blinds
Standard measuring applies: width and height as described above. One additional note for recess fit roller blinds: if your recess is very tight, check that the headrail has room to seat in the brackets. Zebra and double roller blinds need more depth than standard rollers (see recess depth table).
The chain control will be on the side you selected when ordering. Left or right: make sure nothing on that side (a wall return, a cupboard) blocks the chain from hanging freely.
Venetian blinds (25mm and 50mm)
Standard width and height measuring applies. Additional note: when you hold the blind up to measure bracket position, the tilt controls (wand or cord) must have at least 50mm of clearance on each side. If your window is narrow, factor this in when deciding between recess and face fix.
For recess fit, measure the recess depth to confirm the headrail will sit fully inside without the slats hitting the glass when tilted open.
Vertical blinds
Vertical blinds are measured slightly differently because they hang by length, not roll up. The standard rule applies but note these specifics:
Vertical blind measurements
Honeycomb blinds
Standard measuring applies. Check the recess depth carefully: honeycomb blinds have a deeper headrail than standard rollers. For double honeycomb (two fabric layers), add 10mm to the minimum depth requirement.
Outdoor blinds: four measurements
Patio openings are rarely perfectly square. Outdoor blinds therefore need four measurements, not two.
Outdoor blind: all four measurements
Outdoor blinds are not measured against glass doors or windows. They are installed in patio openings, under roof overhangs, and across pergola spans. If you are unsure where exactly your blind will mount, WhatsApp Duncan before measuring.
Minimum recess depths by product
If your window frame is shallower than the minimum for your chosen blind, you have two options: choose face fix instead, or choose a different blind type. Measure the recess depth before ordering.
Custom Fit Guarantee.
Every online order is backed by it. Measure with confidence.
Too large? Return it and we will trim it to size and ship it back, free of charge.
Too small? Return it and we will remake it with a 5% discount and ship it back free.
Unsure before ordering? Send us a photo of the window and your measurements. We will check them before we cut.
Common mistakes
These are the errors we see most often. Every single one results in a blind that does not fit correctly.
Measuring in centimetres
A 5mm rounding error looks tiny on paper. On a window it creates a gap where light floods in around the edge. Always measure in millimetres and record the exact number your tape measure shows.
Using a phone measuring app
AR measuring tools are convenient but they can be off by 10 to 20mm. That is too much for made-to-measure blinds. Use a metal tape measure. No phone, no laser, no guessing.
Making your own deductions
If you subtract clearance before ordering, the blind arrives too small. Our factory knows exactly what to deduct for each bracket type and blind system. Give us the exact window measurement and we handle everything else.
Assuming every window is the same size
Even windows side by side in the same room can differ by 10 to 30mm. Garden Route homes, especially older ones, settle over decades. Every window must be measured individually.
Measuring only once
Three measurements for width (top, middle, bottom) and three for height (left, centre, right). Not because most windows are badly out of square, but because some are, and one bad reading from a single measurement ruins the order.
Not checking the recess depth
Ordering a recess fit blind without checking that the frame is deep enough is the most preventable mistake. Measure the depth before you order. If it is too shallow for the blind you want, choose face fix instead.
Common questions
Do I need to make any deductions from my measurements?
No. Never. Give us the exact window opening measurement and the factory applies the correct deductions for the specific blind type. The deductions differ by product: a roller blind needs different clearance to a venetian, which needs different clearance to a vertical. We know what each needs. If you deduct on your side as well, the blind will be too small.
Should I measure in centimetres or millimetres?
Millimetres. Always. A blind measured in centimetres and rounded to the nearest centimetre can be off by up to 9mm. That creates a visible gap at the edge of a recess fit blind, or a blind that will not sit inside the frame. Your tape measure shows millimetres. Use that number exactly as it reads.
Can I use my phone to measure?
Phone AR apps are fine for checking approximate sizes before you decide what to order. They are not accurate enough for the actual order. They can be 10 to 20mm out, which is too much for made-to-measure blinds. Once you are ready to order, use a metal tape measure. If you do not have one, order your blind and we will include a free tape measure in the delivery so you can verify before fitting.
What happens if my measurements are wrong?
The Custom Fit Guarantee covers every order. If the blind is too large, return it and we will trim it to size and ship it back free of charge. If it is too small, return it and we will remake it with a 5% discount and ship it back free. We also check your measurements before we cut: send us a photo of the window alongside your written measurements and we will confirm before manufacturing begins.
How do I choose between recess fit and face fix?
Recess fit gives a cleaner, architectural look with the frame as the border. It requires enough recess depth for the blind type and no obstructions inside the frame. Face fix mounts above the frame, covers more of the wall, and blocks more light at the edges. It works for any window regardless of frame depth. If you are unsure, send a photo on WhatsApp and Duncan will advise.
For recess fit, do I record the smallest or largest width?
For width: record the smallest of the three readings. This ensures the blind fits inside the frame at its narrowest point. For height: record the longest of the three readings. This ensures the blind reaches the bottom at the highest point. Do not average them. The smallest width and the longest height are the correct measurements to submit.
How do I measure a window with window handles or burglar bars inside the frame?
First measure the recess depth. Then measure how far the handle or bar protrudes from the frame surface. If the protrusion is less than the minimum recess depth for your blind type, you can choose recess fit but the blind will need to sit forward of the obstruction: note this when ordering. If the protrusion equals or exceeds the available depth, choose face fix. Face fix mounts above the frame and the blind hangs in front of everything.
What about sliding doors and patio doors?
Face fix is almost always the right choice for sliding and patio doors. Measure the full width of the door frame and add 100 to 150mm overlap on each side. For height, measure from where the headrail will mount to just above the floor: leave 10mm clearance so the blind does not drag. If you need two blinds side by side across a wide opening, measure the total width and contact us before ordering: we will advise on the correct split so the two blinds meet cleanly in the centre.
Measurement sheet
Use this table to record all your window measurements before ordering. Write down each room, the width and height, and whether it is recess or face fix. Then order online at shop.customblinds.co.za using these exact numbers.
| Room / Location | Width (mm) smallest | Height (mm) longest | Mount type | Blind type |
|---|---|---|---|---|
| e.g. Main bedroom | e.g. 1187 | e.g. 1423 | e.g. Recess | e.g. Roller blockout |
| 1. | ||||
| 2. | ||||
| 3. | ||||
| 4. | ||||
| 5. | ||||
| 6. | ||||
| 7. | ||||
| 8. |
Ready to order?
You have your measurements. The online shop gives you an instant price the moment you enter them. Free delivery nationwide. Custom Fit Guarantee on every order.
Need to talk it through first? WhatsApp 076 022 8410 for orders and general assistance. Or schedule a video call with Duncan directly on 079 523 5407. We are always available for our customers.
Shop online WhatsApp 076 022 8410Duncan Kane Founder, Custom Blinds Shutters and Awnings | 20+ years industry experience"The most common call we get after an order is someone who measured in centimetres and rounded up. The blind arrives 5mm too wide. Measure in millimetres. Write it down. That is the whole job."
Custom Blinds Shutters and Awnings is the Garden Route's indoor and outdoor weather solutions specialist, founded in Knysna in 2010 by Duncan Kane. 8,000+ installations. Full range of roller blinds, venetian blinds, vertical blinds, outdoor blinds, and automation. Shop online at shop.customblinds.co.za with instant quoting, free delivery nationwide, and the Custom Fit Guarantee on every order.
Custom Blinds Shutters & Awnings | South Africa’s trusted window covering specialists since 2010.
