You are mixing up the measurements.
Cereal is measured by weight (i.e. the 20 oz box of Cheerios is 1 1/4 pounds).

The container is measuring volume (i.e. fluid ounces). So the 25 fl oz container will be about 1/5 gallon.

Just imagine you have 1/5 the size of a gallon of milk. Doesn't sound like the cereal will fit.

Looking to organize my cabinets. We buy the 20 ounce box of Cheerios. will they fit in the 25ounce container? I'm stumped as to why the measurements are so much smaller for this brand than the other 'cereal saver' containers (which are 1-3 inches taller and wider and wouldnt fit on our short shelf)

www.containerstore.com/shop/kitchen/foodStorage/specialty?productId=10023965&green=B03A8992-D814-58B1-A474-4F02BD5941D9

Thanks for answering (even if you do roll your eyes at me )