Guide
How to measure for blinds & shades
Getting the numbers right is the single most important part of a great fit. It takes about five minutes per window. Grab a metal tape measure and follow along — and when in doubt, measure twice.
What you'll need
- A steel tape measure (cloth tapes stretch)
- A pencil and a notepad
- A step stool for taller windows
- A few minutes per window
Always record measurements in inches to the nearest 1/8", and always list width first, then height(W × H). It's the industry standard, and it keeps orders from getting flipped.
First, choose your mount
Inside mount
The blind sits neatly inside the window frame for a clean, built-in look. Needs enough frame depth to hold the headrail.
- Tailored, recessed look
- Keeps the sill and trim visible
- Requires adequate depth
Outside mount
The blind mounts on the wall or trim above the opening. Great when the frame is shallow, or to make a window look larger and block more light.
- Best light blocking
- Hides an out-of-square opening
- Makes windows look bigger
Take three width readings (top, middle, bottom) and three height readings (left, centre, right).
Inside mount: use the narrowest width and the tallest height.
Measuring for an inside mount
Windows are rarely perfectly square, so we take three readings each way.
- 1
Measure the width in three places
Measure the exact opening width at the top, middle and bottom. Write down all three. Use the narrowest of the three so the blind clears the frame.
- 2
Measure the height in three places
Measure the opening height on the left, centre and right. Use the tallest of the three so the blind covers the full opening.
- 3
Check the depth
Measure how deep the frame is from the front edge to the glass. This tells us whether the headrail can be recessed. If it's shallow, an outside mount may be the better choice.
- 4
Write down exact opening sizes
Give us the exactopening measurements — don't round or subtract anything. We make the correct factory deductions so the blind fits with the right clearance.
Measuring for an outside mount
- 1
Decide the area to cover
Choose how much of the wall the blind should span. To reduce light gaps and boost privacy, plan to extend beyond the opening.
- 2
Add overlap on the sides
Add at least 1.5"–3" on each sideof the opening to your width so light doesn't sneak around the edges.
- 3
Add height above and below
Add roughly 2"–3" above for the mounting bracket, and as much below as you like for full coverage. Give us the final overall width and height you want.
Common mistakes to avoid
- • Assuming the window is square — always take all three readings.
- • Rounding your numbers — give exact sizes, we do the deductions.
- • Mixing up width and height — it's always width first.
- • Using a cloth tape — only a steel tape stays accurate.
Got your numbers?
Build a free, itemised estimate in a couple of minutes.