DateInterval::format() - Formats the interval DateTime::add() - Adds an amount of days, months, years, hours, minutes and seconds to a DateTime object DateTime::sub() - Subtracts an amount of days, months, years, hours, minutes and seconds from a DateTime object
DateTime::add() - Adds an amount of days, months, years, hours, minutes and seconds to a DateTime object
DateTime::sub() - Subtracts an amount of days, months, years, hours, minutes and seconds from a DateTime object