Dagen tussen 2 datums?
Calculate the difference between two dates and display the result
in days; weeks and days; and other time measurements.
http://www.convertit.com/go/bioresearchonline/calculators/date_and_time/date_time_diff_calc.asp
Op welke dag valt een datum?
Choose a year and month and a calendar is displayed.
http://www.onlineconversion.com/calendar.htm
Tijd optellen en aftrekken 1
Advanced time calculator. add and subtract hours and minutes.
http://www.onlineconversion.com/advanced_time_calculator.htm
Tijd optellen en aftrekken 2
Add and subtract hours and minutes.
http://www.onlineconversion.com/timecalc.htm
Welk jaar is een schrikkeljaar?
Easily determine if a year is a leapyear or not.
http://www.onlineconversion.com/leapyear.htm