Measurement Guide · September 2026

How to Measure Your Windows for an Accurate Blinds Quote

Our online estimate is designed to get you within striking distance of your final invoice before you ever message us — but only if the numbers you feed it are close to real. Here's how our own installers would measure your windows, product by product, so your quote holds up.

Why Measuring Well Actually Matters Here

Every product page on our site prices in real time from two numbers: width and drop (height). Roller, combi/zebra, venetian, and outdoor zip blinds are all billed by square metre — the calculator multiplies width × height, then applies your fabric or slat rate. Curtain tracks are billed by track length instead. Get the width or drop noticeably wrong and your online estimate can be off enough to surprise you later, even though a free on-site survey always re-measures and confirms the real number before anything goes into fabrication.

In other words: a good DIY measurement won't replace the survey, but it will stop the online number and the final number from feeling like two different quotes.

What You'll Need

A retractable steel tape measure, not a soft fabric one — fabric tapes stretch slightly over a metre or two, which is exactly the range most Singapore windows fall into. Measure to the nearest 0.5cm. If you have a laser distance measurer, even better for tall living-room glass panels where a tape sags under its own weight.

Measure every window at three points and use the largest reading — most HDB and condo window frames are not perfectly square, and a blind or track sized to the smallest measurement can leave a visible gap.

Measuring for Roller, Combi/Zebra, Venetian, and Outdoor Zip Blinds

Width: measure across the window opening (or the recess, if you're mounting inside the frame) at the top, middle, and bottom. Use the widest of the three. This is the number that goes into the "Width" field on the calculator.

Drop (height): measure from where the headrail will sit down to your desired end point — sill, floor, or a fixed drop for a bay window — at the left, centre, and right of the window. Use the longest of the three.

Both figures go straight into the cm/ft toggle on the calculator, which then computes your billed area in square metres. A few things the calculator does automatically that are worth knowing about upfront, so your number doesn't look "wrong" when you see it:

The 1.5 sqm minimum catches a lot of Singapore bathroom, bay-window-panel, and study-nook windows — a 90cm × 120cm window (1.08 sqm) is still billed at 1.5 sqm, so don't be alarmed if the on-screen total looks higher than a straight width × height calculation suggests. It's already accounted for, not an error.

Measuring for Motorised Curtain Tracks

Curtain tracks are measured differently because you're pricing a length of rail, not an area of fabric. Measure the total track run — for a straight window this is simply the width of the opening plus your usual side overlap (most Singapore installs run the track 15–20cm past each side of the frame so curtains fully clear the glass when open). DIY Sets run from 1.2m to 5.2m; Customised Tracks extend from 1.2m up to 6.2m, with the track sections modularly joined to fit your exact run.

For an L-shape or U-shape corner track — common on wraparound living room glass or a corner bay — measure each straight section separately rather than the total wall length, since the bend itself takes up a small amount of track. Our L/U-shape bends are fixed at 90°, which is why we always recommend a look at our own measurement diagram for corner and bay window tracks (available on the curtain track product page) before you commit to numbers for a customised bend. Whatever you enter online, the actual runner count and final length is always confirmed at the free on-site survey — this is explicitly called out on the calculator itself because corner geometry is the single easiest thing to get wrong from a tape measure alone.

Drop matters here too, but for style rather than price: a pinch pleat header sits slightly higher above the track than an S/Ripple Fold header, so if ceiling clearance is tight, mention it at survey rather than guessing which heading style will clear a cornice or aircon trunking.

HDB and Condo Specifics Worth Knowing

Standard BTO and older HDB flats often share similar window widths block to block, but "similar" is not "identical" — resale flats especially can have window frames altered during a previous renovation, and even new BTOs vary by facing and floor plan. Treat any published "standard size" as a ballpark for planning your budget, not a number to enter as-is.

HDB bay windows deserve special care: measure each glass panel of the bay individually, since each is priced, cut, and motorised as its own unit rather than one continuous span. If you're deciding between a track and blinds for a bay window in the first place, our HDB bay window guide covers why blinds usually fit the recessed, angled frame better than a curtain track.

For outdoor zip blinds on an HDB or condo balcony, measure the full recess opening including any parapet wall height, and count how many L-shape corner joints your balcony layout will need — each one adds a $80 supporting beam to keep the track rigid against wind load.

Common Measuring Mistakes We See

Measuring once and assuming the frame is square. Most aren't, by a centimetre or two — always take the widest and longest of three readings.

Using a fabric or cloth tape. It stretches under its own tension, which compounds on wider living-room windows.

Forgetting the side overlap for curtain tracks. A track cut exactly to glass width leaves curtains that don't fully clear the window when opened.

Treating a bay window as one width. Each bay panel needs its own width and drop, since each panel is billed and motorised separately.

Skipping the free on-site survey. Even a careful DIY measurement is a planning tool, not a fabrication order — our team always re-measures on-site before anything is cut, so there's no risk in getting your own numbers slightly off. That's what the visit is for.

From Estimate to Final Quote

Once you're happy with your online estimate — you can mix and match windows across any product category in the same cart — send it to us on WhatsApp to book your free on-site survey. That visit is where your DIY numbers get double-checked against a professional measurement, any corner or bay window geometry gets finalised, and your motor sizing gets confirmed before fabrication begins. For a sense of what happens after that, see our guide on how long installation takes, and if you want the full picture on what different window types typically cost, our 2026 pricing guide breaks it down by product.

Frequently Asked Questions