I have been making these totes as thank you presents for three years now for my children's class teachers. This year I went with the following measurements:
w: 49cm x h:22cm for the top rectangle.
w: cm x h: 30cm for the two outer bottom rectangles
w:13cm x h: 30cm for the bottom middle rectangle
Back was w:49cm x h:52cm
1.5cm seams throughout
You can see the front on the picture below:
I also made some inside pockets. One was a flat one and the other was a stand out one, I used directions from Lisa Lam's "Bag Making Bible" book. They were all fully lined.
I went with three colour ways (the teacher's favourite colours) and my children embroidered the hearts.
I hope you like them as much as the teacher's did. I think these make a great present, and tend to be much appreciated by the receiver.