How to Measure Windows Correctly for Blinds
Knowing how to measure windows for blinds correctly is the most important step in achieving a clean, professional finish. Even the highest-quality blinds will not perform or look right if measurements are inaccurate. Incorrect sizing can lead to light gaps, poor insulation, uneven operation, and an overall unfinished appearance.
This guide explains the correct way to measure windows for blinds, using clear, practical steps that homeowners can follow with confidence.
Why Accurate Window Measurement Matters
Blinds are precision-made products. A difference of just a few millimetres can affect how well they fit and function. Accurate measurements ensure:
Proper light control and privacy
Smooth blind operation
Reduced light gaps
A neat, built-in appearance
Long-term durability
Measuring correctly also helps determine whether a recess fit (inside mount) or face fit (outside mount) is the better option for your window.
Tools You’ll Need Before Measuring
Before you start measuring windows for blinds, gather:
A steel measuring tape (essential for accuracy)
A notepad or phone to record measurements
A pencil
A step stool if windows are high
Avoid fabric or flexible tapes, as they can stretch and cause inaccurate readings.
Step 1: Decide Between Recess Fit and Face Fit
Recess Fit (Inside Mount)
Blinds sit neatly inside the window frame, creating a streamlined, modern look. This option works best when the window recess is deep enough to accommodate the blind.
Face Fit (Outside Mount)
Blinds are mounted on the wall or architrave, covering the entire window opening. This option is ideal for shallow recesses or when you want maximum light block and privacy.
Your measuring method depends on which fit you choose.
How to Measure Windows for Recess-Fit Blinds
Recess-fit blinds must fit within the window opening, so precision is critical.
Measuring Width
Measure the width of the recess at three points: top, middle, and bottom
Record the smallest measurement
This ensures the blind will fit without rubbing or jamming.
Measuring Drop (Height)
Measure from the top of the recess to the window sill
Take measurements on the left, centre, and right
Record the smallest measurement
Always measure in millimetres for the best accuracy.
How to Measure Windows for Face-Fit Blinds
Face-fit blinds provide greater coverage and are more forgiving, but correct sizing is still essential.
Measuring Width
Measure the window opening
Add at least 70–100 mm on each side for proper coverage and reduced light gaps
Measuring Drop (Height)
Measure from where the blind will be mounted (above the window) down to the desired finish point
Common finish points include the sill, below the sill, or the floor
This approach is especially effective for bedrooms and living spaces requiring enhanced privacy.
Common Measuring Mistakes to Avoid
When learning how to measure windows for blinds, avoid these common errors:
Measuring only once instead of at multiple points
Using approximate or rounded measurements
Mixing up width and drop
Measuring in centimetres instead of millimetres
Assuming all windows in a room are identical
Each window should always be measured individually.
Measuring Special Window Types
Bay Windows
Measure each section separately, accounting for angles and join allowances.
Sliding Doors
Measure the full width and height of the opening, typically using a face-fit installation for better coverage.
Windows with Handles or Obstructions
Ensure there is enough clearance so blinds operate freely without hitting handles or frames.
Measuring Special Window Types
While this guide helps homeowners understand how to measure windows for blinds, professional measuring ensures absolute accuracy—especially for custom blinds. Professional measurements:
Eliminate costly mistakes
Account for fitting tolerances
Ensure the best visual and functional result
For made-to-measure blinds, professional measurement is always recommended.
Final Thoughts
Learning how to measure windows for blinds correctly saves time, avoids installation issues, and ensures your blinds look and perform exactly as intended. Whether you choose a recess fit for a sleek finish or a face fit for maximum coverage, careful measuring is the foundation of a successful result.
