Add and subtract hours, minutes, and seconds (and more) with Calc Zero: Time.

Calc Zero: Time supports 26 different time units, including seconds, hours, minutes, days, and many more. Shortcut M.SS and H.MMSS keys let you enter time units quickly and easily. For example, enter 2.33 [M.SS] + 3.37 [M.SS] = 6 min 10 sec. Similarly, 2.3515 [H.MMSS] would be treated as 2 hr 35 min 15 sec.

As with all Calc Zero apps, unit conversions are fast and easy. Enter the number, tap the unit to convert from, and tap the unit to convert to.

As with all Calc Zero apps, math operations on like units are fully supported, so it's easy to increase or decrease recipes.

And as with all Calc Zero apps, fractions are fully supported, and the Equals key is optional (i.e., you can use RPN mode if you prefer).