Blind Size Calculator
Calculate the perfect blind dimensions for your windows with inside or outside mount options
Calculate Blind Size
Blind sits within the window frame
Blind extends over the window frame
Width Measurements
Measure the width at three points: top, middle, and bottom of the window frame
Height Measurements
Measure the height at three points: left, center, and right of the window frame
Uncheck to subtract 1/4" for clearance above the sill
Recommended Blind Size
Enter all measurements to see your recommended blind size
Example Calculation
Standard Living Room Window
Mount Type: Inside Mount
Width measurements: Top: 36", Middle: 35.75", Bottom: 36.25"
Height measurements: Left: 48", Center: 48.5", Right: 48.25"
Touch sill: Yes
Calculation
Width = Smallest measurement = 35.75"
Height = Largest measurement = 48.5"
Recommended Blind Size: 35.75" × 48.5"
Measurement Tips
Use a Metal Tape Measure
More accurate than fabric measuring tapes
Measure to 1/8 Inch
Precision is important for proper fit
Check for Square
Compare diagonal measurements
Mount Types
Inside Mount
- ✓Clean, built-in appearance
- ✓Shows window trim
- ×Requires square window frame
Outside Mount
- ✓Better light blocking
- ✓Makes windows appear larger
- ✓Hides uneven frames
Understanding Blind Measurements
Why Multiple Measurements?
Windows are rarely perfectly square due to settling, construction tolerances, or age. Taking measurements at multiple points ensures your blinds will fit properly and operate smoothly.
Inside Mount Rules
- •Use the smallest width measurement to ensure clearance
- •Use the largest height measurement for full coverage
- •Subtract 1/4" from height if clearance is needed above sill
Outside Mount Rules
- •Use the largest width measurement plus 3" for 1.5" overlap on each side
- •Use the largest height measurement plus 1.5" for top overlap
- •Provides better light control and privacy
Pro Tip: If width variation exceeds 1", consider outside mount for better appearance and function.
Common Window Types
Picture Windows
12" to 96" high, 24" to 96" wide
Slider Windows
24" to 60" high, 36" to 84" wide
Double Hung
36" to 72" high, 36" to 84" wide