Dive Computer

A wrist or console device that tracks depth and time in real time and continuously calculates a diver's no-decompression limit and ascent guidance.

A dive computer is the instrument that answers the two questions every diver keeps asking: how deep am I, and how long can I stay. It samples depth and time constantly and runs a decompression algorithm to display your remaining no-decompression limit, so instead of planning a whole dive to its deepest point with tables, you get credit in real time for the shallower parts of a multilevel dive.

Beyond depth and NDL, computers monitor your ascent rate and warn when you exceed it, most enforcing something in the 9 to 18 m per minute range depending on the model, and they prompt the standard 3 minute safety stop at 5 m. Nitrox models track oxygen exposure once you set the mix, and air-integrated models show tank pressure and remaining gas time from a transmitter.

Popular algorithm families include Buhlmann ZHL-16C with gradient factors and RGBM. After the dive, the computer stores the full profile, and apps like SeaLog can import those logs so your depth curve, temperature, and surface interval history live in one logbook.