This question gets asked VERY frequently. A search would bring up a whole bunch of similar questions.

A century is 100 miles done as all-at-once as possible. Therefore, if you can do 100 miles with no stops ... great! If you need to stop for some breaks along the way in order to make it through the century ... no problem!!

Most organised centuries are capped at 8 hours or so, but there is at least one where you're allowed as much as 24 hours (if not a bit more). It depends on commonly expected weather and terrain conditions ... and it is a good idea to find out what sort of time limit there is for any organised century you're considering. Most organised centuries also have several rest stops along the way, which you can take advantage of as desired.

If you're doing an unorganised century, you can take as long as it takes for you to finish the century, generally with cap of 24 hours (a day), to allow for adverse weather and terrain. (I've done centuries in ideal conditions in 6 hours and a century in bitterly cold and icy conditions in 15 hours, and everything in between.) You can also stop whenever you feel like for whatever you deem a "reasonable" length of time.

What would not be a century would be (for example) if you rode 50 miles on a Saturday afternoon, came home, mowed the lawn or went grocery shopping, spent the rest of the evening watching TV, slept the night, got up early and finished the 50 miles on Sunday morning. That would be two 50 mile rides. You get the idea ... the time of the bicycle should be reasonably brief.


And incidentally ... when you tell people how long it took you to do the century, include the amount of time you were off the bicycle for a total ride time. If Person A does a non-stop century in 5 hours, and and Person B does a century in 7 hours = 5 hours of ride time & 2 hours off the bicycle, it would be inaccurate and disrespectful for Person B to announce that he/she did a 5-hour century.