Splitting your wide window into two shades instead of ordering one oversized unit improves durability, reduces shipping risks, lowers costs, and gives you more flexible light control. But many customers then ask: How exactly should I measure when buying two shades for one wide window? This guide walks you through it step by step.

Decide Your Mount Type First

Before measuring, confirm whether you’re choosing:

  • Inside Mount (installed inside the window frame)
  • Outside Mount (installed above and outside the window frame)

The measuring method differs slightly for each.

a comparison highlighting the visual difference between an inside mount and an outside mount for shades on a wide window

Inside Mount: Measuring for Two Shades

Inside mount gives a clean, built-in look. When splitting into two shades, the goal is to ensure smooth operation while minimizing the center light gap. 

① Measure the Full Inside Width
Measure the inside width of your window frame at three points: top, middle, and bottom. Use the smallest measurement as your reference width. For a quicker method, you can simply measure across the top inside edge of the frame.

Example:
If the three measurements are 96", 95 3/4", and 96 1/4", use 95 3/4" (smallest) or 96" (top).

② Manually Deduct Clearance (Important)
Important: Unlike some manufacturers, we do not automatically deduct any width during production. The size you order is the exact size that will be made.

For inside mount installation, you must manually deduct a small clearance to ensure smooth operation and proper fit inside the window frame. We generally recommend: 

Deducting 3/8" ~ 5/8” total from the full inside width.

Example:
Measured width: 95 3/4"
Deduct 1/2" → 95 1/4" adjusted width

③ Divide the Adjusted Width Into Two Sections
Now divide the adjusted width evenly:
95 1/4" ÷ 2 = 47 5/8"

You would order:
Two shades at 47 5/8" width each

④ Understand the Center Light Gap
All shades have brackets and fabric deductions on each side.

a technical diagram shows how to measure and calculate the width for two inside-mount blinds on a single wide window frame

Outside Mount: Measuring for Two Shades

When installing two shades side by side, there will be a small light gap in the center (usually about 1/2"–1"). This is normal and unavoidable due to necessary fabric deductions. Choosing an outside mount can help minimize light leakage along the left and right edges, providing better overall light control. 

①Measure Total Desired Coverage Width
For outside mount, measure the full area you want the shades to cover — not just the glass. We typically recommend extending 2–4 inches beyond the window frame on each side. This improves privacy and reduces side light leakage.

Example:
Window frame width: 96"
Add 2" on each side → 100" total coverage width

②Divide the Width
Now divide your total coverage width into two sections.

Example:
Two shades at 50" each

Because outside mount is installed on the wall, there is no need to deduct clearance for fitting inside a frame.

a technical diagram shows how to measure for an outside mount, adding extra width to the wide window for full coverage and light control

Height Measurement (Same for Both Shades)
For both inside and outside mount:

  • Measure full height carefully
  • Both shades should use the same height

Measure Height for Inside Mount
Measure height at left, middle, and right. Use the longest measurement.

a graphic explains how to measure the height at three points to find the most accurate fit for two inside-mount shades on a wide window

Measure Height for Outside Mount
Measure vertically from the installation point down to your desired coverage endpoint (window sill or floor) on either the left or right side.

a graphic explains the correct points to measure the total height required for two outside-mount shades on a wide window

Again, the ordered height will be produced exactly as specified. Please double-check measurements before placing your order.

Additional Practical Considerations

When ordering two shades, decide where you want the operating controls:

  • Controls on outer sides (most common and visually balanced)
  • Controls in the center

Most homeowners prefer controls on the outer edges for a cleaner appearance.

Final Thoughts

When splitting a wide window into two shades, the key steps are simple:

  • Measure accurately
  • Record the measurement rounded down to the closest 1/8"
  • Deduct clearance manually for inside mount
  • Divide evenly
  • Double-check before ordering

Because we manufacture exactly to the size you submit, precise measurement is essential. Taking a few extra minutes to measure correctly ensures your shades fit properly, operate smoothly, and perform beautifully for years to come.