Time to Surface

Technical dive planner & decompression calculator for iPhone

Free to plan, no account, and signed team plans without limit. Your own logo, name and colour on them come with the Diver.Today App Family subscription.

Staged decompression from 15 to 51 metres — deeper to 56 with a warning — on six bottom gases, with one deco bottle. Runtime, stops, minimum gas and both cylinder fills, before you kit up.

What it plans

Staged decompression, 15 m to 51 m, and to 56 m with a warning rather than a refusal.
Six bottom gases — EAN32, triox 30/30, EAN28, air, 21/35 and 18/45.
One decompression gas — EAN50 or oxygen — in an AL80, AL50 or AL40, on a twinset back gas you pick.
Bühlmann ZH-L16C, gradient factors yours to set, 20/85 by default.
ppO₂ 1.2 bar working, 1.6 bar at a stop by default — stricter than the 1.4 most divers trained at. Both adjustable.
Descent and ascent rates you set — 10 m/min down, 9 m/min to the first stop, 3 m/min between stops, and the last 6 m at 1 m/min.
Minimum gas, the workbook's C × A × T: what two divers on one back-gas supply need to leave the deepest point and reach the surface, at the minimum ascent rate rather than the planned one.
Deco bottle fill and reserve, walked level by level from the schedule that was actually solved, not estimated.
CNS, and which of back gas, deco bottle or CNS ends the dive.
Repetitive dives — keep a plan under a name, then say up to three came before this one, each with its surface interval. Nitrogen and helium both cross the interval; CNS decays at a 90-minute half-time.
On-the-fly adjustments, re-solved — five minutes more or less, or three metres deeper or shallower, each run through the same model rather than scaled by a rule of thumb, with the change in deco minutes and gas.
Pragmatic decompression, off by default — a simplified profile for the water, not a more conservative one.
A wetnote page, one tap, sized to copy onto your slate by hand.
Metric or imperial.

What it does not plan

Closed-circuit rebreathers. Cave or wreck penetration. Hypoxic mixes and travel gas. More than one decompression gas. Altitude — sea level only. It does not compute OTU.

It refuses rather than warns

Inside its envelope: a gas past its oxygen limit, an exposure past the maximum, cylinders that will not cover the plan, a surface interval under an hour — all produce no numbers at all, rather than a number with a caution attached.

Your dive computer owns the dive

This is pre-dive arithmetic. It never pronounces a dive safe, and it is not a substitute for training, for your computer, or for your own judgement in the water.

Worked examples

Real figures from the app's own reference dive and pinned test cases: