Free. Current App Store rating: 3 stars
Time-tracking apps and Web-based tools abound. But Toggl Timer is one of the easiest to use and most flexible. The app's straightforward interface makes it simple to start and stop timers, even when you're offline. You have to remember to stop and start those timers, of course. If you forget, you can manually adjust entries. The app shows several days of completed tasks, and you can add tags to entries for sorting. The app syncs with Toggl's cloud-based service as well as with the Toggl desktop apps for Mac and Windows. If you upgrade to Toggl's $5 monthly plan, you can add hourly rates to your tasks to quickly see how much moolah you've made.