How to Measure Your Windows for Custom Screens (DIY Step‑by‑Step Guide)

The most common reason for ill‑fitting mosquito screens is incorrect measurement. Even a 2mm gap can let mosquitoes through, and an overly large screen may not fit into the frame at all. Measuring for custom‑made screens is easy – you just need a metal tape measure, a pen, and about five minutes per window. This guide walks you through the process for the most common American window types, with tips for no‑drill installations.

Tools You’ll Need

• Metal tape measure (fabric tape can stretch; avoid it).
• Pen and paper (or a note taking app).
• A small step ladder if your windows are high.
• Optional: level to check if your window frame is square (if it’s noticeably out of square, contact us for special instructions).

Always measure in millimeters (mm) or decimal inches. We recommend mm for precision. Note: MBORMC screens are cut to the exact dimensions you provide – so accuracy is critical.

General Rule: Inside Mount vs. Outside Mount

Most windows use inside mount – the screen fits inside the window frame (the “rebate” or “reveal”). Measure the width from the left interior edge to the right interior edge, and the height from the top interior edge of the frame to the bottom sill where the screen will rest.

For windows with very shallow frames (less than 10mm depth), an outside mount may be better – the screen attaches to the wall or frame exterior. In that case, measure the width of the entire window opening (including the frame) and the height from above the frame to below the sill. Contact us if you are unsure which mount type suits your window.

Step‑by‑Step for Common Window Types

Casement Windows (Crank‑Out)

Casement windows open outward using a crank. The screen must fit inside the frame and not interfere with the crank handle.

1. Open the window slightly to access the interior frame.
2. Width: Measure from the left inside edge of the frame to the right inside edge. Take three measurements: near the top, middle, and bottom. Use the smallest of the three – this ensures the screen will not be too wide.
3. Height: Measure from the top inside edge of the frame to the bottom inside edge (where the screen will rest). Measure left, center, and right; use the smallest.
4. Note the location of the crank handle – our H01 retractable screen can be installed above or below the handle. We will adjust the cassette position accordingly.

Sliding Windows (Horizontal)

Sliding windows have two sashes that move left/right. The screen usually mounts on the track behind the sliding sash.

1. Open the sliding sash to expose the full track.
2. Width: Measure the distance between the left and right stops (the vertical frame edges). Measure at the top and bottom; use the smaller measurement.
3. Height: Measure from the top of the track to the bottom sill. Measure left and right; use the smaller.
4. If you want a retractable screen, we will mount the cassette on the side opposite the sliding sash – indicate left‑hand or right‑hand operation.

Double‑Hung Windows (Vertical Sliding)

Double‑hung windows have two sashes that move up and down. A screen is usually placed on the lower half.

1. Open the lower sash a few inches.
2. Width: Measure the distance between the left and right side tracks (where the sash slides). Measure at the top, middle, and bottom of the lower opening; use the smallest.
3. Height: Measure from the top of the lower sash (when closed) down to the sill. Measure left, center, right; use the smallest.
4. For a full‑height screen that covers both sashes, measure the full height from the top of the upper sash stop to the sill. Contact us for custom height screens.

Awning Windows (Hinged at Top, Push‑Out)

Awning windows are similar to casement but hinge at the top and push outward at the bottom.

1. Push the window open a few inches.
2. Width: Measure inside the frame from left to right. Take three measurements (top, middle, bottom) and use the smallest.
3. Height: Measure from the top inside edge down to the bottom inside edge. Use the smallest measurement.
4. A retractable screen (H01) mounted at the top works well because the window pushes out below it.

French Doors & Sliding Patio Doors

For FD05 folding screens on French doors or sliding doors:

• Width: Measure the full width of the door opening from left jamb to right jamb. If the doors are bi‑parting (two panels), measure the entire width as a single number. We will split the width into two equal panels unless you specify otherwise.
• Height: Measure from the top of the door frame down to the floor. If there is a threshold, measure to the top of the threshold (the screen will sit above it).
• Indicate whether you want a bottom track (recommended for stability) or a track‑less version (clamp brackets only).

Common Mistakes to Avoid

• Using a cloth tape measure – it stretches and gives inaccurate results.
• Measuring only once – always measure at least three points (top/middle/bottom for width; left/center/right for height). Windows are often not perfectly square.
• Forgetting about obstacles – handles, cranks, locks, and alarms may protrude. Note their positions so we can design the screen to avoid them.
• Rounding down or up – Provide the exact measurement in mm or inches to one decimal. We will produce the screen to that dimension. Do not add or subtract extra “just in case”.
• Measuring after painting or new trim – if the window frame has been recently modified, wait until the work is complete before measuring.

How to Record and Send Your Measurements

Write down each window:

• A unique name or number (e.g., “Kitchen left window”)
• Width in mm (or inches) – e.g., 1200mm
• Height in mm – e.g., 1500mm
• Window type (casement, sliding, etc.)
• Any notes about obstructions (e.g., “crank handle 200mm from left edge”)

Send this information through our inquiry form or directly via WhatsApp. We will then produce a custom quote and advise on the best product for your window type.

What Happens After You Send Measurements?

Our team will review the dimensions and confirm the feasibility. For most windows, we will recommend the H01 retractable (casement/awning/double‑hung), H05 velcro (rental‑friendly), or FD05 folding (French doors). We will then produce a CAD drawing for your approval (if requested). Production takes 7‑15 days, then shipping. You will receive a tracking number.

DIY Installation After Receiving Your Screens

With correct measurements, installation is straightforward:

• H01 retractable: Clean the frame, peel the adhesive tape backing, press the cassette into place, then attach the guide rails. Pull the mesh down and hook it. Done.
• H05 velcro: Clean the frame, stick the hook side of the tape, then press the mesh onto it. That’s it.
• FD05 folding: Assemble the top track, clamp it to the door frame, hang the folding panels, then adjust the tension. Full instructions and video provided.

No tools required for H01 (adhesive version) and H05. The FD05 requires a screwdriver to tighten clamp brackets (still no drilling).

Need Help? Contact Our Support Team

If you’re unsure about any measurement, take a photo of your window (from the inside) and send it to us via WhatsApp. We will give you specific guidance. Chat with us now →

Accurate measurement is the first step to a perfect‑fitting, mosquito‑free home. Follow this guide, and you’ll be enjoying fresh air without bugs in no time.