The filter fit, and does the job. It's hard to gauge the size of the filter from the old one, but the hood housing itself has a width of 35 3/4 (to fill a 36 inch opening).
The interior holder for the filter has an outside measurement of 18.5 inches which widens to 19 3/4 at the top and a vertical rise of 2 7/8". The filter slides up into clips on the sides