… another variant: s1=1125899906840000 s2=1125899906842625 As you can see float to string conversion is not portable across systems and PHP…: it can be used to workaround signed vs. unsigned int issues; it helps with float formatting; always a saviour. UPDATE: as Jakub…, but setting precision=16 (enough to hold 2^53 in decimal without sign) helped in all cases. However at the moment…