Blind Size Calculator
Enter the window or recess width and height, choose inside or outside mounting and the blind type. The calculator gives the blind size to order, the roller fabric width and how much of the window the raised blind covers.
- Blind width and drop
- Inside or outside
- Stack height
For a recess, measure the width at the top, middle and bottom and use the smallest.
Inside a recess the blind is a little narrower. Outside it overlaps. For a recess, take about 10 mm off the width so the blind clears the walls. For an outside mount add about 75 mm each side and 100 mm to the drop to block light. A 1,200 × 1,200 mm window takes a 1,350 × 1,300 mm outside-mount blind.
Blind size chart
Outside mount, roller. Search for a window.
| Window (mm) | Blind width | Drop | Fabric width |
|---|---|---|---|
| 600 × 900 | 750 | 1000 | 715 |
| 900 × 1200 | 1050 | 1300 | 1015 |
| 1200 × 1200 | 1350 | 1300 | 1315 |
| 1500 × 1200 | 1650 | 1300 | 1615 |
| 1800 × 1350 | 1950 | 1450 | 1915 |
| 2400 × 1500 | 2550 | 1600 | 2515 |
Sizes in mm.
Window width and blind
Outside mount, 1,200 mm high. Slide the window width.
The blind is drawn half lowered over the window.
How to measure for a blind
Recess or frame. Step through it.
Choose mount
Inside or outside.
Check handles and sills. An outside blind may need to clear a handle that sticks out.
Roller, roman or venetian
Blind types. Compare them.
Simple.
Folds.
Slats.
Blackout fabric works best outside the recess, where the overlap blocks edge light.
Before ordering
Blind checks. Tick each item.
Tick each item as you go.
Child safety: keep cords out of reach with a cleat or choose a cordless blind.
What you get
Blind sizing. Each tile explains one result.
Blind.
Blind.
Roller.
Raised.
Type.
Tell the maker whether your size is the recess or the finished blind, as some deduct for you.
Frequently Asked Questions
No question matches that search.
How do I measure for an inside recess blind?
Measure the recess width at three heights, use the smallest and take about ten millimetres off.
How much should an outside blind overlap the window?
About seventy-five millimetres each side and a little more at the top and bottom.
What is the drop of a blind?
Its height from the headrail to the bottom when fully lowered.
Why is roller fabric narrower than the blind?
The brackets and control take up about thirty-five millimetres.
What is stack height?
How much of the window the blind covers when fully raised.
Should I fit blinds inside or outside the recess?
Inside looks neater. Outside blocks more light and suits shallow recesses.
Do roman blinds block much of the window when raised?
They stack to roughly fifteen per cent of the drop plus a little.
A blind that fits first time
Measure carefully, choose the mount and add or deduct the right amount, and the blind fits neatly.
More size calculators
Each one has its own calculator, worked examples and answers to common questions.