The dive computer buying guide

A dive computer continuously tracks your depth and time and calculates how much no-decompression time you have left — replacing dive tables with a live, personalised readout. Here's how to choose one without drowning in spec sheets.

1. Start with how you dive

Your dive style narrows the field faster than any spec. Be honest about where you are now and where you'll be in two years:

• Occasional warm-water diver: a simple recreational computer (Peregrine, Zoop Novo, Puck Pro+) is plenty.
• Frequent diver building toward deeper or nitrox dives: a colour recreational unit with an upgrade path to air integration.
• Heading into technical, trimix or rebreather diving: buy a technical computer now (Perdix 2, Petrel 3, Teric) so you don't replace it later.
• Want one device for diving and daily life: a watch-style computer (Teric, Descent, D5).

2. Display & readability

Underwater, glanceability beats everything. Three broad display types:

• Segmented LCD (Zoop Novo, Mares Quad): high-contrast, sips battery, very legible — but limited graphics.
• Full-colour LCD (Peregrine): clear colour coding for warnings and modes at a moderate price.
• AMOLED (Teric, Suunto Ocean, Descent Mk3i): brightest and sharpest, best in low visibility; costs more and needs charging.

3. The algorithm (and why not to overthink it)

The decompression model decides how much bottom time and what stops you get. The common families:

• Bühlmann ZHL-16C + Gradient Factors — the de-facto standard on Shearwater and many others; transparent and tunable for conservatism.
• Suunto Fused / RGBM — Suunto's bubble-aware family across its range.
• DSAT / dual-algorithm — found on some Oceanic and Aqua Lung units, often with a choice of two models.

For recreational diving the practical differences are modest. Diving conservatively within whatever model you have matters far more than which model it is.

4. Air integration

Air-integrated computers display tank pressure — and true gas-time-remaining (GTR) — on the same screen as your depth and no-stop time, fed wirelessly by a transmitter that screws into your first stage. It's a genuine convenience and a nice safety cross-check, but it's optional, and on many computers you can add a transmitter later.

5. Nitrox, trimix & modes

Check the modes you'll actually use: air, nitrox, gauge and freedive cover nearly all recreational diving and are near-universal today. Trimix and CCR (rebreather) support is the dividing line for technical computers. Multiple gas switches matter if you'll do staged decompression.

6. Power: replaceable vs rechargeable

User-replaceable batteries (including AA on the Petrel 3) are ideal for liveaboards and remote travel — no charger, no power anxiety. Rechargeable computers are tidier day to day but need a top-up before every trip. Pick for your logistics, not for marketing.

7. A quick pre-purchase checklist

• Does it support every mode you'll dive in the next two years?
• Can you read it instantly at depth, in the conditions you actually dive?
• Does the battery type fit how and where you travel?
• Is there an air-integration path if you want it later?
• Does it log dives and sync to an app you'll actually use?

Ready to shortlist? See our best picks by use-case, or browse by wrist, console, technical and beginner computers.