Lumina (with sync)

Lumina is the iPhone counterpart of the most used time tracking tool for the desktop.
Lumina is focused to show you a simple way to track your time.
The concept of Lumina is based on three columns.

Projects: A project is a bundle of tasks
Tasks: A tasks is a bundle of durations
Durations: A duration is the smallest brick to calculate your total time

For more productivity, Lumina has also a desktop application and you can sync your times between multiple iPhones and Macs via the Lumina Cloud.