About the Blind Size Calculator
Blind width and drop for inside or outside recess fitting, with the overlap allowances.
Also known as: roller blind size, blind measurement calculator, recess blind size, window blind dimensions.
How to use this calculator
- Enter recess width, recess height, fitting, blind type and the other fields.
- The result updates instantly as you type — press Calculate (or Enter) at any time.
- Review the breakdown shown under the main result.
- Use Copy result or Share to save the answer or send a link with your inputs.
Formula
inside fit = recess − clearance · outside fit = recess + overlap
Worked example
Using the values pre-filled in the calculator above:
- Recess width = 1,200 mm
- Recess height = 1,400 mm
- Fitting: Inside the recess
- Clearance each side = 5 mm
- Blind type: Roller
the calculator returns:
- Order size: 1,190 × 1,395 mm
- Blind width: 1,190 mm
- Blind drop: 1,395 mm
- Fabric area: 1.66 m²