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
Check a deco gas switch for isobaric counterdiffusion risk: Burton rule of fifths, dissolved-gas load before/after, and the minimum helium your deco gas needs.
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.