Crossing the International Date Line does not in itself contribute to jet lag, as the guide for calculating jet lag is the number of time zones crossed, with a maximum possible time difference of plus or minus 12 hours. If the time difference between two locations is greater than 12 hours, one must subtract that number from 24. For example, the time zone UTC+14 will be at the same time of day as UTC−10, though the former is one day "ahead" of the latter.