Plastic GBC Comb Bindings | How to Choose a Binding Size

If you need to know the best way to choose a GBC comb binding size, then Binding101.com is the place to find your answer! In just 2 simple steps, and referencing out easy-to-use chart, we will guide you to the industry-recommended comb binding spine size for the specific thickness of your book.

① Measure Document Thickness - First, let's find out your book thickness. You can do so by following these two easy steps.

    Ⓐ Place your entire stack of pages to be bound on a table, including your binding covers.
    Ⓑ Use a ruler to measure the thickness of the stack, without pressing it down.
    Ⓒ Add 1/8" to that measurement.

Remember to let your stack lay loose without pressing it down tight when you measure it. If you press it down, you run the risk of the pages being hard to turn or even ripping, as the GBC comb size may end up being too small for your book. As an example, we are going to say that we have a 1/2" thick document.

② Determine GBC Comb Size - Next, we need to determine the best comb binding size for your document thickness. We can do this using the comb binding chart below.

Comb Diameter Sheet Capacity* Comb Shape
1/4" 11 - 25 Sheets Round
5/16" 26 - 45 Sheets Round
3/8" 46 - 65 Sheets Round
7/16" 66 - 80 Sheets Round
1/2" 81 - 100 Sheets Round
9/16" 101 - 120 Sheets Round
5/8" 121 - 145 Sheets Round
3/4" 146 - 165 Sheets Round
7/8" 166 - 185 Sheets Round
1" 186 - 210 Sheets Round
1 ⅛" 211 - 235 Sheets Round
1 ¼" 236 - 260 Sheets Oval with Locks
1 ½" 261 - 310 Sheets Oval with Locks
1 ¾" 311 - 360 Sheets Oval with Locks
2" 361 - 425 Sheets Oval with Locks


Example - My book measures about 1/2" thick, laying loose. When I add 1/8" to that, I get a total thickness of 5/8". Using the chart above, my 5/8" thick document will work best with a 5/8" binding comb. Always round up - having a binding comb that is slightly too large is better than one that is too small and cannot be used.

Still need help? No problem! Call our experts at (866) 537-2244 for one-on-one help finding the best binding spine size.


Mallory Morsa, Binding101 Product Expert About the Author • Mallory Morsa is the product expert and content specialist at Binding101, and has been a valued team member since 2008. She started her career here in customer service, moved onto sales supervisor, product management, and then onto content. She takes a hands-on approach to products, and truly gets to know how every item works before she writes about them, with a goal to give you all of the honest information you need to make a confident buying decision. She has a bachelor's degree with a focus on management and marketing, and has been a writer, photographer, and videographer for many years. In her free time, she loves to read by the pool, volunteer at the local animal shelter in the kitten nursery, and snuggle her three furbabies while she binge watches Netflix.


* Comb binding sheet capacities are approximations, and are determined using standard 20 lb. bond copy paper. The actual sheet capacity will vary depending on the materials being bound.