Dive computers have come a long way. Early technical computers were bulky, offered a single mode and were difficult to set up. Today they fit on your wrist like a watch, have colour displays, handle several breathing gases and can be configured in minutes. Yet there is still a fundamental difference between a recreational computer and a true technical diving computer, and for decompression dives the choice matters a great deal. This guide explains what distinguishes a technical computer, which features to look for and what to check before you buy.
How a technical computer differs
Recreational computers are designed mainly to keep you within no-decompression limits. Once you go beyond 40 metres, plan decompression stops or breathe several gases during one dive, you need a computer that calculates decompression for trimix and multiple gas switches, and shows you clearly what to do next.
The decompression algorithm
Most technical computers today use a variant of the Bühlmann ZH-L16C algorithm. It models 16 theoretical tissue compartments with different half-times for taking up and releasing nitrogen and helium, and from them calculates your decompression ceiling.
What matters in practice are gradient factors. The low value determines how deep your first stop will be, the high value how close to the limit you surface. Lower values mean a more conservative profile. Many divers choose more conservative settings after several days of repetitive diving, in cold water or when tired. The right starting point depends on your training – your instructor will recommend one.
Redundancy: always a backup
A basic rule of technical diving is that every critical piece of equipment has a backup. With an hour of decompression ahead, you do not want to discover that your only computer has failed. That is why technical divers:
- carry at least two independent computers, each with its own battery,
- set both for the same gases, so the backup can take over immediately,
- often choose different models or even manufacturers, to rule out the same software fault in both.
Have a plan independent of the computer
Many technical divers also carry their dive plan with backup runtimes on wetnotes or a slate. If both computers fail, the plan still tells you which stops to do and for how long.
Key features of a technical computer
Support for multiple gases
A recreational computer handles air and perhaps nitrox. For technical diving you need:
- trimix – mixtures of oxygen, nitrogen and helium,
- gas switching during the dive – bottom, travel and decompression gases,
- individual ppO₂ settings for each gas.
A typical deep profile starts on trimix, continues on a travel gas such as EAN50 and ends with pure oxygen during the last stops. The gas switch should take only a few button presses. The cylinders for these gases can be found among our tanks and accessories.
Display readability
You will read the display often – in the beam of a torch, in murky water or in bright sunlight near the surface. Look for a high-contrast display with large, clear figures for depth, time, ceiling and the next stop, and scratch-resistant glass that survives handling heavy equipment.
Controls
At depth, with narcosis and task loading, you do not want a complicated menu. The most frequent actions – switching gas, checking the ceiling or the maximum depth – should be reachable in one or two presses. If you dive in dry gloves, the buttons must be large enough to operate reliably.
Alarms
Sound alarms are easy to miss in a hood. Look for vibration alarms, clear visual warnings and adjustable depth and time thresholds. Vibration is especially popular among cave divers.
GPS and compass
GPS works only at the surface – it can mark your entry point, help you return to it on the surface and record the coordinates of the dive in your log. Underwater, navigation relies on a compass.
Connectivity and data analysis
A good computer lets you download detailed profiles to an app, analyse gas consumption and decompression and share data with your buddy or instructor. Looking back at your actual profiles helps you plan similar dives better.
What to check before you buy
- Depth rating – it should comfortably cover the depths you train for and plan to reach.
- Battery life and charging – on expeditions, charging is not always possible.
- Service and support – how quickly you can get help or spare parts if something breaks abroad.
- Firmware updates – algorithms and functions evolve, and your computer should keep pace.
Browse our dive computers. A mechanical pressure gauge remains a reliable companion to any computer – see our regulators and gauges.
DIVEBRAIN DB-01 in our range
For technical diving we offer the DIVEBRAIN DB-01. According to the manufacturer’s specifications it offers:
- the Bühlmann ZH-L16C algorithm with adjustable gradient factors,
- up to five gases per dive, each with its own ppO₂ setting,
- a 240 × 240 pixel display protected by Corning Gorilla Glass,
- five buttons, with gas switching in a few presses,
- three adjustable depth and three time alarms, with sound, vibration or both,
- GPS for marking the entry point and logging dive locations,
- the DiveStory PRO app for downloading and analysing dives,
- up to 25 dives on a single charge and a depth rating of 100 metres.
Even with a reliable computer, the rule of redundancy applies: always carry a second one.
Frequently asked questions
Can I use a recreational computer for technical diving?
Not for decompression dives with multiple gases. Most recreational computers cannot handle trimix, several gas switches or long decompression, or they lock out after a deco violation.
Why do I need two computers?
If your only computer fails during a decompression dive, you lose the information you need to surface safely. A second, independent computer set for the same gases takes over immediately.
Which gradient factors should I use?
That depends on your training, experience and the conditions. Start with the settings your instructor recommends and only change them once you understand their effect on your profile.
Do I need air integration?
It is convenient, but not essential. Many technical divers rely on a mechanical pressure gauge, which needs no battery or wireless signal.
Conclusion
A technical diving computer is not a gadget – it is equipment you rely on to bring you back safely. Choose a model with a reliable algorithm, clear display and simple controls, always carry a backup, and keep learning from every dive you download. If you are just starting out, read our guide on how to get started with technical diving, and if caves attract you, our article on cave diving safety and equipment.