DaysCalc offers you the ability to calculate the number of years, months and days between two dates, or the date a given number of years, months and days from another date. And it does it the easy natural iPhone way.
The iPhone image on the left shows that Tony Blair's New Labour governed Britain 13 years and 9 days: from the time they were elected on the 2nd of May 1997 till they were replaced by the Conservative-Liberal Coalition on the 11th May 2010.
The iPhone image on the left is live. You can click with your mouse on the buttons to navigate from one view to another, like on a real iPhone.