Curtains & Windows

Blind Size Calculator

Convert window measurements into an inside- or outside-mount blind order size.

Free interactive tool

Enter your details

m
m
m
Method & guidance

How the Blind Size Calculator works

Inside mounts subtract a fitting deduction; outside mounts add overlap for better light control.

How to use this tool

  1. Collect accurate values for opening width, opening height, mount type.
  2. Enter measurements in the displayed units and select the choices that match this project.
  3. Select Calculate / Generate, then compare the outputs with the stated Blind Size Calculator method.
  4. Apply the result only after checking product specifications and real site conditions.

Example calculation or use case

For a worked Blind Size Calculator example, use Opening width = 1.2 m, Opening height = 1.5 m, Mount type = Inside recess, Deduction or overlap each side = 0.01 m. The tool then applies this method: Inside mounts subtract a fitting deduction; outside mounts add overlap for better light control.

Frequently Asked Questions

What information does the Blind Size Calculator use?

It uses the measurements and choices shown in the form. Inside mounts subtract a fitting deduction; outside mounts add overlap for better light control.

How accurate is the Blind Size Calculator result?

The calculation is mathematically consistent with the stated assumptions. Always follow the blind manufacturer’s exact measurement and deduction policy. Real products, site conditions, and supplier specifications can still change the final decision.

Should I include an allowance?

Use the result as a planning baseline and keep a sensible reserve for site variation, delivery, or fitting.

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