Product review (3 stars): Buy the HC26E1004 instead, much better quality and same size
Buy the Honeywell HC26E1004 Humidifier Pad instead of this one.  The 1004 pad is more durable, wider, and only costs about 2 bucks more.  For me, it fit my whole house humidifier better.  The paper pad fit the humidifier but could have been a good 1/2 inch wider and still fit.  I can feel more humidity in the air after replacing the paper one.  Definitely need this in a dry Denver winter.

The dimensions on these filters are approximately 10x13x1.5