Pilot ToolBox will help you with all of your needs in aviation.

Night Time Calculator
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Night time calculator will allow you to calculate your flights' night time according to departure and destination airport, block times, and date. This feature doesn't require an internet connection.

Time Calculator
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Time calculator will help you to calculate your flight times easily without any errors. Also if you can see the calculation history just double-tapping the result label. Editing and partial summing are very easy on the history screen.