Compare these two measurements. Hold the measuring tape in line with the centers of the bolt holes. How To Measure For A Toilet Seat Toilet Seat Toilet Seating If it looks more like the size of a grapefruit or softball you need a jumbo 3 inch seal. How to measure for a toilet . Measure the bowls length and width. Locate the closet bolts on your old toilet. Video of the Day. If measuring for a replacement toilet just measure from the back wall to the center of the toilet drain and write down the measurement. Make sure you measure the holes that are closest to the toilet rim itself. For a standard toilet the rough-in measurement should be between 11 inches and 13 inches. The width of a toilet seat is measured from the middle of the toilet bowl which happens to be the widest part of the bowl. Usually the distance is 12 inches so a standard toilet will fit just fine in this space. Harris 2021 April 16 How do you measure for a new to. Do not measure from the b...