Include time of day to calculate the exact duration down to the second. Repeat functionality: make multiple calculations at the touch of a button. Include locations to calculate a duration across time zones and handle DST changes. See your results in alternative time units, i.e. the total number of seconds. Export and share results. Year range: 1-3999. Developed by timeanddate.com, the number one online provider of accurate and reliable time and date related information worldwide. The free version of the app is funded by advertising. The upgrade removes advertising via an in-app purchase.