When you are talking about percentage, it simply means a certain value out of 100, whereas percentile has nothing to do with that. On the contrary, percentile simply means a value below which you can find a certain percentage of values. The symbol to represent percentage is denoted as "%", while you only indicate percentile with Xth, where X happens to be a numerical figure e.g. 20TH. Percentages do not have quartile, but percentiles do.
Percentages are not based on ranked number but percentiles are. Percentages can be expressed in form of ratio and decimal, whereas you cannot express percentiles in those forms. Percentile relies on a normal distribution, but percentage does not. Percentage is known to be based on one case, whereas percentile is based on comparing one case with several other cases. Percentage is more of a mathematical quantity, while percentile is used more in statistics.