Recommend simple time tracking software

I am looking for software that can help me keep track of how I spend my time. For the time being I am only tracking how I spend my time, not, say, a whole team working on a project.

To date I’ve been using a google spreadsheet to type in my time but that gets kind of tedious.

One thing I need is a way to manually enter the time in a helpful way. I’ve seen many systems that work with a timer. You start the timer when you commence a task, and then hit the timer again when you finish. That sounds great in theory, but what if you forget to start the timer? Or what if you are away from your computer and keeping track of your time on a piece of paper and need to enter it later?

Also I would like to be able to do a periodic review and see, for example, how much time I spend on various tasks. That is one big headache with using a spreadsheet to track time: I have to go through later and manually calculate. And in practice, I don’t do that.

Thanks for your recommendations.