Diving tools and calculators

The planning maths every diver needs, running the same Buhlmann ZH-L16C engine as the Diving Standard app and Apple Watch. Free, and no account needed.

• No-stop time (NDL) — Work out your no-stop time at any depth on air or nitrox, from the same Buhlmann ZH-L16C model that runs on the Diving Standard app and Apple Watch. Free, no account.
• Nitrox & MOD — Maximum operating depth, ppO2, equivalent air depth and best mix for any nitrox blend, at a 1.4 or 1.6 bar limit. Free, no account, same engine as the app.
• Gas & SAC planner — Work out your surface air consumption, how much gas a planned dive needs, and whether your cylinder covers it with a reserve. Free, no account needed.
• Deco planner — Plan decompression stops and total ascent time on Buhlmann ZH-L16C with gradient factors, from the same engine as the Diving Standard app and Apple Watch.
• Scuba weighting — Work out your scuba weighting from your suit, cylinder, BCD and body, with a line-by-line breakdown of where each kilo comes from. Free, no account.
• Freediving weighting — Work out freediving ballast for your suit, lungs and discipline, balanced at 10 to 15 metres so you always float at the surface. Free, no account.