SCUBA Diving Reference

Dive Ref does the gas sums an Open Water or nitrox diver works out on a slate, and shows the working behind every answer. Use it on the boat, the beach or the bank, before the dive and after it. Air and nitrox to EAN40. Depths to the recreational limit of 40 m or 130 ft. No account, no network, nothing leaves the device. GAS Set your oxygen a percent at a time, or pick air, EAN32 or EAN36. Dial a depth and Dive Ref tells you in a line whether the gas is safe to breathe there, and if it is not, how shallow to stay. Maximum operating depth at your working oxygen limit, with the 1.6 bar contingency figure beside it Oxygen partial pressure at the dialled depth Equivalent air depth for nitrox The best nitrox for a depth, rounded down, loaded with one tap DIVE Build a no-stop dive as one level or several. Descent, ascent and a 3-minute safety stop at 5 m are added for you and drawn on a profile. Gas for the dive, in bar on your cylinder and in litres breathed Minimum gas, the reserve that brings you and an out-of-air buddy to the surface, with every term shown Turn pressure by halves or thirds The pressure you surface with, in red if it dips into minimum gas Oxygen exposure (CNS) for the dive A no-stop check on every plan, Bühlmann ZH-L16C at gradient factor 85, with the minutes to spare or a plain warning that the dive needs stops Measure your breathing rate from a timed swim or a logged dive. Save dives by name, search them, and share any plan as a slate card. LEARN 27 diving terms in plain English, from Boyle's law to minimum gas, each with what it means and why it matters. Search by word or by meaning. TOOLS Cylinders: the free gas in common metric and imperial cylinders at any gauge reading, and the weight of that gas Weighting: the lead to add going from fresh water to salt, and the buoyancy swing from a full cylinder to an empty one A converter for pressure, depth, volume and temperature Settings for units, salt or fresh water, altitude, breathing rate, oxygen limit, turn rule and descent and ascent rates SHOW THE WORKING Every result opens to show its formula, then the same formula with your own figures in it. Every tab has a help page explaining each control and each result. ONE PRESSURE MODEL Set salt or fresh water, altitude and metric or imperial once, and every tab follows. On first launch Dive Ref takes metric or imperial from your device. IPHONE AND IPAD On iPad the inputs and the results sit side by side, in every orientation. PRIVACY Dive Ref makes no network requests. No account, no analytics, no tracking. Saved dives stay on the device. REQUIREMENTS iPhone or iPad with iOS or iPadOS 26.0 or later No in-app purchases. No subscriptions. No advertising. Dive Ref is a planning tool, never a dive computer. It assumes no diving earlier in the day, and it does not plan decompression stops. Dive within your training, analyse every cylinder before use, and let your computer and your buddy have the last word.