A dive computer monitors aspects of a dive, commonly including depth and time, and uses a programmed model to display information such as no-decompression limits, ascent-rate warnings, and surface intervals. Features vary by device, and divers must learn the specific computer they use.
What information can it show?
Depending on the model, a computer may show current depth, maximum depth, dive time, water temperature, ascent rate, no-decompression information, decompression obligations, cylinder pressure, and logs. Not every computer includes every feature, and the values depend on correct settings and use.
What a dive computer cannot do
It cannot guarantee that decompression illness will not occur, decide whether conditions are suitable for you, or replace a dive plan and gas reserve. A computer can also be misconfigured, damaged, or run out of battery. You need to understand its limits and have a plan for equipment failure.
How to use one responsibly
- Read the manufacturer’s manual and learn its alarms and settings.
- Set the correct breathing gas and other relevant parameters.
- Monitor depth, time, gas supply, buddy, and surroundings—not only the screen.
- Follow your training agency’s procedures and the dive plan.
- Do not switch computers or planning systems mid-dive without understanding the implications.
Bottom line
A dive computer is a useful monitoring tool, but safe diving still depends on training, conservative planning, equipment checks, and judgment.
What information does a dive computer provide?
A dive computer tracks information such as current depth, elapsed dive time, and ascent rate, and uses a programmed model to estimate decompression status. Depending on the model, it may also display water temperature, maximum depth, no-decompression time, safety-stop guidance, and cylinder pressure when paired with compatible equipment. Exact functions and terminology vary, so the manual is essential.
How to use a dive computer responsibly
Learn the device’s settings and alarms before diving, and set the correct gas and other required parameters according to your training. Monitor the display regularly, but do not stare at it so much that you lose awareness of your buddy or surroundings. A computer cannot guarantee that decompression illness will not occur, and it does not replace planning, gas management, or staying within your training limits.
After the dive
Review your profile and log the dive, noting unusual conditions, gas consumption, and any issues. Check the manufacturer’s guidance for battery care, cleaning, software updates, and service. If the computer gives an unfamiliar warning, do not guess what it means underwater. Learn the appropriate response during training and ask a qualified instructor or the manufacturer for clarification before your next dive.