if you notice i said it was 14 inch and i needed 9 1/2 so i should have bout 2 1/2 inch left over... for those of you who did the math let me explain lol the length is 14 the width is 12. im leaving the length to 14 and cutting the 12 inch down to 9 1/2 to fit the ten gallon tank. thats why i said 2 inch or so