Tools
Dive planning calculators.
Quick, browser-based tools for gas planning and dive analysis. No login, no tracking, just open and use. Metric units throughout; toggle between salt and fresh water where it matters.
Nitrox & Trimix Gas Blender
Blend any nitrox or trimix by partial pressure, or work out the result of topping off a tank. Ideal-gas or real-gas (van der Waals) maths.
Open toolMOD & END Calculator
Maximum operating depth for any nitrox mix, and equivalent narcotic depth for trimix planning.
Open toolSAC Rate Calculator
Work out your surface air consumption from a single dive: pressure used, time, average depth, and cylinder size.
Open toolRock Bottom & Rule of Thirds
Minimum gas for a safe two-diver ascent from depth, plus rule-of-thirds turn pressures. Gas planning from depth, SAC rate, and cylinder size.
Open toolICD Gas Switch Checker
One deco gas switch, three rules: Burton rule of fifths, the 0.5 bar nitrogen step at depth, and Doolette's timing and oxygen checks, with a recommendation.
Open toolDCS Risk Probability
Live implementation of the published Marroni 2026 multifactorial DCS model (127,957 dives, AUC 0.910). Each predictor explained with the underlying physiology and the peer-reviewed evidence.
Open toolThese work offline too. Every calculator here is also in Deco Room, the dive theory app, which needs no signal — which is where you actually want them. See the apps.
Important: These tools are aids for trained divers. They do not replace formal training, dive planning software, or the judgement of a qualified instructor. Always cross-check critical numbers and follow your training agency's standards.