Biking has become more appealing to people trying to save money on gas. Biking is also an environmentally friendly alternative to driving, and it gives you a workout while allowing you to enjoy the scenery along your route. You won't enjoy your bike ride if you aren't comfortable on the seat, so having the right seat, also known as a saddle, is important. The way your bottom fits on the saddle is what really counts, so you have to measure yourself first. Once that's done, you can find the right bicycle seat width to suit your needs.
Place the cardboard on a low surface like a short step stool or curb.
Sit on the cardboard and lean forward into the position you use when riding. If you're going to be casually riding around town, you'll probably sit more upright than if you're going to be racing or riding for exercise, in which case you'll be bent forward more at the waist.
Stand and measure between the center points of the indentations made by your ischial tuberosity, or sit bones. Write down the measurement.
Visit a bike shop and find the style of seat you need. Saddles for cruising bicycles are wider than seats for racing bikes, and each style comes in variations.
Find a seat that looks like it might be comfortable and look for the pads on the part of the seat where your bottom sits. Measure between the center points of the pads. If that measurement matches or is close to the distance between your sit bones, sit on the seat and test for comfort.