The dive planner in Suunto D5 helps you to quickly plan your next dive. The planner displays available no decompression time and gas times for your dive based on depth, tank size and gas consumption set.
The dive planner can also help you plan dives in series, taking into account the residual nitrogen from your previous dive(s) based on the planned surface time you enter.
It is important to adjust tank size, tank pressure and personal gas consumption to get the gas calculations right.
See How to plan a dive using the Dive planner for details on planning your dives.