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“Envelope Basics: Measuring – Part 2” is part of an occasional series titled “Envelope Basics” that provides an in-depth look at all-things envelopes – elements, measurements, ordering tips and more*.

Last week, we looked at the correct way to measure an envelope. This week, we’re going to elaborate on envelope window measurements, so you’ll be completely and confidently prepared to give proper specifications for your next mail campaign. Remember: providing accurate information at the start of the project helps your campaign run smoothly and can help you avoid unexpected delays.

You can find examples of custom window envelopes here.

An envelope’s window position is measured by the distance from the left side and the distance from the bottom of the envelope. The envelope’s window size is always indicated as height by width, regardless of the window’s orientation.

How to Measure an Envelope Window

  1. Orient the Flap
  2. Measure Window Placement
  3. Determine Window Size
  4. Identify Window Orientation
  5. Specify Window Design

Step 1. Orient the Flap

Before measuring for window placement, the envelope should be oriented so the flap is at the top. This is essential whether it’s an open side or open end envelope.


How to measure an envelope window step 1: Orientate the flap

Step 2. Measure Window Placement

Window placement is measured from the left first, and then from the bottom of the envelope.

How to measure an envelope window step 2: Measure the window placement

Step 3. Determine Window Size

Window dimensions are listed vertical by horizontal and reflect the window opening versus the window patch.

How to measure an envelope window step 3: Determine window size

Step 4. Identify Window Orientation

How to measure an envelope window step 4: Identify window orientation

While most windows are horizontal formats, it’s good practice to specify horizontal or vertical orientation. Horizontal windows are parallel to the bottom of the flap and the vertical measurement is shorter than the horizontal measurement. Vertical windows are perpendicular to the bottom flap and the vertical measurement is longer than the horizontal measurement.



Step 5. Specify Window Design

How to measure an envelope window step 5: Specify window design

Envelope windows are available in a variety of shapes and sizes, and can be used to attract attention. Windows can be custom specified according to a design request (e.g. dog bone window opening).

Download Our Guide envelope basics guide

Envelope Basics is a complete guide that details everything you need to select, measure and order the right envelope for your mail campaign.

Whether you’re a seasoned mailer or new to the mail industry, Envelope Basics includes helpful tips for your business or organization. Download your copy of Envelope Basics here.

As always, your Tension sales representative is happy to work with you to ensure accurate window and envelope measurements. You can also reference our guide, “Envelope Basics: Measuring” on SlideShare for more details. Contact us today to discuss more about your project and envelope sizes. 

*This blog is intended for informational purposes only. Exact envelope and/or print specifications should be discussed in detail with your sales representative.