TimeCalc is a very simple utility for calculating times. I use it for calculating splits or predicting race times. It is a calculator that supports doubles and times. For example:
If I run 5 kilometers at 3:30/kilometer, the race will take me 17:30.
> 5*3:30
17:30
If I want to know how fast my splits need to be in order to run a 10K in 37:00.
> 37:00/10
3:42
If I want to add two times:
> 3:42 + 3:30 + 3:49
11:01
Or calculating the splits Bekele needs to run on the marathon:
> 2:02:13 / 42.195
2:54
Which is very fast, indeed.