Stand next to a solid wall with your bike—you’ll use the wall to support yourself as you test the seat height. Next, stand over your bike and squeeze the brake. Put your hand on the wall for support, and hop on the saddle. Pedal backwards a few times, and stop when one leg is at the 6 o’clock position.
Now position the ball of your foot on the pedal, and straighten your leg. If you can’t fully straighten your leg, raise your saddle. If your knee is locked, but you’re still stretching to reach the pedal, lower your saddle. Hop off the bike to raise, lower, and make small adjustments.
You’ll know you have the right fit if you’re only able to touch your toes to the ground when you’re sitting on the saddle. If your feet are flat on the ground, your seat is too low. When you think you’ve found the right height for you, ensure the saddle is straight by lining up the saddle’s nose with the top tube, and tighten the clamp.