Time Calculator is a free utility for iPhone that allows you to perform mathematical operations with values in hours, minutes, and seconds. Its intuitive interface is ad-free, and quick-and-easy to use for purposes ranging from fitness to science. Calculations can be performed between time and standard numbers when multiplying or dividing.

Time Calculator is particularly useful in time-based sports such as running, swimming, rowing to calculate splits and paces and to convert times between distances.

How to use: After entering a number, simply press H (hours), M (minutes), or S (seconds) to select the unit of the number. Then enter an operation and another number.