How to

Measuring Guidelines for New Window Treatments

The following information is intended to provide general guidelines for measuring your windows for new treatments. Having a Hirshfield’s professional installer measure the project for you will produce the most accurate results.



• Hunter Douglas window fashions are custom fabricated according to the dimensions given on your order.
• Measurements must be exact to ensure a proper fit.
• The fabricator will not be held accountable for incorrect measurements.

Measuring Dos and Don’ts

• Do always measure the exact window intended for the treatment. Each window opening is unique.
• Do always use a 3/4″ or 1″ steel tape measure.
• Do measure the width and write it down; then measure the height and write it down.
• Do measure to the nearest 1/8″ (except all shutter products, measure to the nearest 1/16″).
• Do follow all product specific instructions in this guide.
• Don’t assume a window is square.
• Don’t take any deductions. Factory deductions will vary based on product and mounting selection. Please refer to individual product specifications or contact your fabricator for more information.
• Standard measuring procedures apply to all products that fit rectangular windows unless otherwise specified.
• Careful attention must be given to each measurement; measurements that pertain to the mounting areas (headrails) are critical and must be accurate.
• Specialty shapes and applications require special measuring procedures. Please contact Hirshfield’s and have a professional installer measure for a trouble-free installation.

Inside Mount or Outside Mount?

Inside (IB) Mount – Shade fits within window frame.

Outside (OB) Mount – Shade overlaps window opening.

Be sure to add the desired overlap amount to each side and then add to the total ordered width when ordering an outside mount shade.

End (EB) Mount – Shade is mounted at the top left and right side corners.


Standard Measuring Procedures

Inside (IB) Mount

1. Be sure the window opening is deep enough to install the mounting bracket. Refer to the Mounting Charts for recessed mounting depths for each product.
2. Measure the width inside the window opening at the top, middle and bottom. The top measurement is critical because the headrail must fit. The top measurement should always be the ordered width. Vertical applications require a top measurement only; middle and bottom measurements are not required.
3. Measure the height inside the window opening at the left, right and center.
4. Measure the window on the diagonal. If the 2 diagonal dimensions are not exactly the same, it may be necessary to specify an outside mount for optimal light control and privacy.
5. The ordered width should ensure a precise fit for the headrail and allow proper operation of the shade. If widths in the window vary, order the minimum width necessary to allow the shade to go up and down.
6. The ordered height should ensure clean operation at the base of the window as well as provide maximum privacy and light control. If heights in the window vary, order the shortest height for vertical treatments and the longest height for horizontal treatments — except Silhouette® and Nantucket™ shadings, where the shortest height should be ordered to allow for full rotation of the bottom rail.

Outside (OB) Mount

1. Measure the desired width and height. To minimize light leakage, the shade should overlap the window opening at least 2″ on each side and at the bottom. Refer to the Mounting Charts for recommended overlaps for each product.
2. When measureing the height, take into account the requirements for mounting the bracket attachment.

Note • Measuring guidelines for shutters and wood cornices often vary from that of other products. Please contact your Hirshfield’s representative on Bridgeway® specialty shapes, Heritance®, NewStyle®, Express™ NewStyle® and Palm Beach™ shutter sections, as well as the Country Woods® Exposé™ wood cornices for specific information.


1. Measure the overall width. Use the narrowest measurement with inside mounts. With outside mounts, we recommend 3″ overlap on all sides.

2. Without moving the tape, measure the location of the desired split (usually a vertical mullion).

3. Enter all measurements on the order form — overall width, left panel width, center panel width (if required), right panel width and height.

4. All panel widths combined must equal the overall width.

5. The smaller panel must be at least 1/3 the size of the larger panel (Silhouette® and Nantucket™ window shadings, and Vignette® Modern Roman Shades only).


• For a window opening that is to be fully uncovered when the treatment is drawn open.

• For outside-mounted treatments.

1. Measure the desired uncovered width, rounding your measurement down to the nearest 1/8″. With side stack units, include the desired amount of overlap for the side opposite the fabric stack in this measurement. Refer to product specifications for recommended overlaps, also taking into consideration trim or molding.

2. Using the stackback charts created for the product in each product section, locate the uncovered width (clear opening) measurement under split stack or side stack design.

3. Find the corresponding “stackback” for that range.

4. Add the stackback to the uncovered width to get the correct width to order.

5. After determining the correct width to order, confirm that there is enough room to outside mount the treatment on the opening at that width.


A cut-out is a shade with a small rectangular area removed from it to avoid obstructions, usually from one of the corners or from the bottom. Not all products allow cut-outs. Refer to the specific product section to verify availability.

Measure a cut-out like a standard rectangular shade, but also provide detailed measurements of the area to be removed. In addition, mark your measurements on a sketch of the cut-out to ensure accurate communication of the order.

CORNER WINDOWS: Butt and Bypass Shades

When 2 shades butt against each other at a corner, as shown in the overhead views at right, 1 shade is the “butt” shade and the other is the “bypass” shade.

Measure each shade separately using the procedures just described, and then subtract headrail depth from the butt shade to obtain the proper ordering width.

With outside mounts, remember to allow for overlap on the sides and at the bottom. Refer to the Mounting Charts for headrail depth for specific products.

CORNER WINDOWS: When Not Using Butt and Bypass

Some window treatments such as Luminette® Privacy Sheers cannot use the butt and bypass. They are then measured to meet in the corner.

1. Measure the width of both openings to the common corner.

2. Deduct the necessary depth of the treatment (deduct 3″ for Luminette Classic, or 4″ for Luminette Quintette™) from the width of each measurement so they will meet in the corner but not overlap. Note: If spacer blocks or extension brackets will be used for extra clearance on outside mounts, add the amount of extra clearance to the deduction.

3. Order the width less the deduction for each window.


With bay windows, location of the window treatment and the ordered width are marked and measured as illustrated at right.

1. Determine the depth of the product you are mounting (use 3″ for Luminette Classic, and 4″ for Luminette Quintette) and use this for the width of your poster board.

2. Cut 2 pieces of poster board (depth determined from #1 above) wide by 12″ long. Note: If spacer blocks or extension brackets will be used for extra clearance on outside mounts, add the amount of extra clearance to the width dimension of the poster board before measuring.

3. Place the strips in the left angle first and bring them together until the front corners of the poster board meet. Mark points A and B.

4. Repeat this step for the right side angle, marking points C and D.

5. Measure between points B and C to obtain the width measurement of the center window treatment.

6. Measure from point A outward to the desired width to obtain the width measurement of the left window treatment.

7. Measure from point D outward to the desired width to obtain the width measurement of the right window treatment.

The above represent only some of the various window configuations that may be present in your home. They are intended to serve only as general guidelines. All window fashions have their own unique installation methods so for best accuracy and optimal results, Hirshfield’s recommends that your installer provide the measurements.