# Turn Pressure — No-deco scuba gas planner > No-deco scuba gas planner (iPhone/iPad app by RUSTAM ISMAILOV.) - Source: https://appshunter.io/ios/app/turn-pressure/id6801749776 (this page in markdown: same URL + `.md`) - Developer: [RUSTAM ISMAILOV](https://appshunter.io/developer/6799582362) - Category: Sports, Utilities - Price: Free - Age rating: 4+ - Requires: iOS 17.0 · 4 MB - Languages: American English - Released: 2026-09-01 - Data updated: 2026-09-06 - User reviews in markdown: https://appshunter.io/ios/app/turn-pressure/id6801749776/reviews.md ## What is Turn Pressure? Most divers were taught one number: surface on 50 bar, or 500 psi, no matter the depth, the cylinder, or who they're diving with. It's not that nobody plans — it's that the plan never changes with the dive. Turn Pressure runs the actual numbers instead. Tell it how deep you're going, what you're carrying and who's breathing it, and it gives you a turn pressure, the minimum gas to get two divers up from the deepest point, and a bottom time — before you kit up. It's a no-stop, recreational planner. It doesn't plan decompression dives, stage gases or bailout, and it isn't meant to run during the dive — plan with it on the boat or the night before, then go by your gauge and your computer in the water. WHAT MAKES IT DIFFERENT Minimum gas that scales. Most calculators hand you a flat reserve. Turn Pressure works from the actual volume two divers need to reach the surface, for the cylinder you're actually carrying — the same ascent from 30 m needs 64 bar from a 15-litre steel and 86 bar from an aluminium 80. Same dive, same divers, different tank, different number. A bottom-time limit for your gas, not just your air. Full Bühlmann ZH-L16C no-stop calculation for air, EAN28, EAN32 and EAN36, with gradient-factor presets from 30/70 to 100/100 — including 15/85 — defaulting to 40/85, so you can match whatever your computer is set to. Repeat dives use the dive you actually did. Tell it how deep you went and how long you were down, and it works out what nitrogen is still in you across your surface interval — instead of guessing at a dive it cannot see. If you don't tell it, it doesn't guess: it shows you nothing and says why. An ascent you can brief. The way up is a ladder of levels — each with its own time and depth, labelled on the chart, and each one a depth to hold or be shallower than. And when the no-stop limit ends the deep part of a dive, the plan spends the remaining gas at 9 m instead of sending you up with a full-looking gauge. One number, not two. Bottom time is whichever runs out first — your gas or your no-stop limit — and Turn Pressure tells you which one it was, so you know if you're gas-limited or NDL-limited before you're in the water. Your SAC rate, not an average off a chart. Type your own number, start from a tier, or work it out from one real dive's numbers — depth, time, cylinder, start and finish pressure. Turn Pressure keeps it as a dated list with a trend chart so you can watch it improve. Metric and imperial done properly. 100 ft and 130 ft, AL80 and HP100 — the numbers each system is actually dived in, not arithmetic conversions like 98 ft or "81 cu ft." EVERYTHING ELSE • Turn pressure on thirds, halves or all-usable gas • Single, or double/sidemount — 10 L and 12 L steel, aluminium 80, 15 L steel • Maximum operating depth for every mix, hard-blocked at ppO2 1.4; planning to 40 m, sea level only • Ascent rate you choose, 3 to 9 m/min — the reserve follows it and never shrinks • Two ascent profiles: NDL with a safety stop (a stepped ascent with 3 minutes at 5 m), or a staged minimum-decompression ascent — 9 m/min to half your depth, then 3 m/min with a minute at every 3 m up — whose bottom times come from a published recreational schedule rather than from the model, and which plans EAN32 to 30 m because that is what the schedule covers • Saved briefs for the dives you run over and over • Works with no signal, on any boat, anywhere Free. No account, no ads, no analytics, no network access at all — nothing leaves your phone. This is a planning tool, not a dive computer and not a decompression planner. Your training, your gauge and your computer decide the dive. Turn Pressure just does the arithmetic beforehand. ## Version history (last 3 releases) ### 1.2 — 2026-09-05 The app asks for your breathing rate once, and now offers all three ways to answer it: from a dive you did, the number off your computer, or a tier. There is a way past it too — skip for now and it plans on the typical tier, marked as a preset rather than as yours, until your first logged dive replaces it. The starting fill now ends at the cylinder's own rating. An 11.1-litre aluminium 80 stops at 207 bar and the steels at 232, so a plan can no longer be funded on gas the cylinder cannot legally hold. Minimum gas does not depend on the fill, so this shortens dives rather than reserves. Settings says each thing once. Every footer is one line you act on, and what is true but read once now sits behind the (?) in its section heading — which opens as a full sheet at large text sizes, so it can be read to the end. ### 1.1 — 2026-09-02 The ascent is now a ladder of levels, not a slow drift. Half your depth, then 5 m, with a middle level on some plans — each with its own time and depth on the chart, and each one a depth to hold or be shallower than. A plan you can brief and check a computer against. A dive the no-stop limit ends no longer surfaces with gas to spare. The plan spends the remaining gas at 9 m, where coming off the deep segment the gas runs out long before the nitrogen does. Deep dives on big cylinders gain the most. Ascent rate is now a setting, 3 to 9 metres a minute, default 9. The reserve follows it: plan a slower ascent and the reserve grows, and it never falls below the 9 m/min figure. The Minimal Decompression Profile keeps its own prescribed ascent. Minimum gas now covers the whole ascent. It used to be worked out as far as the safety stop, which left the last five metres unfunded; it runs to the surface now. And ascent time is charged exactly instead of rounded up to the whole minute, which removed a jump in the reserve between neighbouring depths. The two changes mostly cancel: from 30 m it is still 64 bar out of a 15-litre steel and 86 out of an aluminium 80; from 40 m the reserve is 2 bar higher. Maximum operating depth now states the fact about the gas: air reads 56 m at ppO2 1.4. The app still plans no deeper than 40 m. The plan screen was redrawn — sliders for depth, time and fill, a depth label on every step of the profile, and the card says plainly what ends the dive. Your reserve funds a straight ascent at the rate you planned. It is not a budget for a slower one. ### 1.0 — 2026-09-01 No release notes. ## More apps by RUSTAM ISMAILOV - [Four & Six Breathing Exercise](https://appshunter.io/ios/app/four-and-six-breathing-exercise/id6799582360) - [Time to Surface](https://appshunter.io/ios/app/time-to-surface/id6803187271) - [Weights Check](https://appshunter.io/ios/app/weights-check/id6806640499) All apps by RUSTAM ISMAILOV: https://appshunter.io/developer/6799582362 --- *Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-09-06.*