# Bar to PSI and Litres to Cubic Feet: Dive Unit Converter (Dive Kit)

_Last updated: 2026-10-30_

> A free web converter at https://divekit.app/tools/dive-unit-converter/ for bar to psi (1 bar = 14.5038 psi) and the other numbers divers convert: pressure (bar, psi, MPa), volume (litres, cubic feet), depth (meters, feet), temperature (°C, °F, K), weight (kg, lb) and breathing rate (L/min, ft³/min, bar/min with a cylinder volume). It runs the same @divekit/core code as the Dive Kit app's Unit Converter. Free, no account.

## Who is the dive unit converter best for?

- **Divers travelling between metric and imperial regions**: a briefing in meters, a cylinder stamped in psi, a buddy's computer in feet.
- **Divers converting a breathing rate** between L/min, ft³/min and bar/min on a given cylinder.
- **Divers reading a US cylinder chart in litres**, or the reverse; the page explains why an AL80's 80 ft³ and 11.1 L are different quantities.
- **Dive shop staff** handling gear and fills for international customers.

## Formula

```latex
1\,\text{psi} = \frac{0.45359237 \times 9.80665}{0.0254^2 \times 10^5}\,\text{bar}, \quad
1\,\text{ft} = 0.3048\,\text{m}, \quad
1\,\text{ft}^3 = 28.316846592\,\text{L}, \quad
{}^\circ\mathrm{F} = {}^\circ\mathrm{C} \times 1.8 + 32, \quad
\text{bar/min} = \frac{\text{L/min} \times 1.01325}{V_\text{cyl}}
```

V_cyl is the cylinder's water volume in litres. 1 MPa = 10 bar, 1 lb = 0.45359237 kg, K = °C + 273.15.

## How does Dive Kit compute it?

- Every conversion is core's, in decimal arithmetic, so a round trip returns the value typed. Results show at most two decimals; a factor line shows six significant digits (1 bar = 14.5038 psi).
- Units are chosen per conversion and do not follow the page's metric/imperial setting, as in the app.
- Depth converts as a length. The pressure at a depth also depends on water type (Dive Kit counts 10.00 m per bar of EN 13319 water by default, 10.20 m in fresh water).
- bar/min converts to L/min only through a cylinder's water volume (default 12.2 L); that conversion is ideal gas. The SAC and RMV calculator measures both from a real gauge drop.
- Temperature stops at absolute zero (−273.15 °C, −459.67 °F, 0 K).
- A non-zero result too small for two decimals shows three significant digits instead of 0. The cylinder volume for bar/min stays at 1 L or more.
- The page carries reference tables computed at build time: bar to psi and MPa, psi to bar, meters to feet and back, water volume against the free gas contained at 15 °C and the rated-basis gas at 70 °F for eight common cylinders, and SRMV in L/min, ft³/min, bar/min (12.2 L) and psi/min (AL80).

## How does it compare?

| | Dive Kit web converter | Dive Kit app (Unit Converter) | Generic unit converter |
|---|---|---|---|
| Diving units in one place | Pressure, volume, depth, temperature, weight, breathing rate | Same | Spread across categories |
| Breathing rate with cylinder volume | Yes (bar/min) | Yes | No |
| Explains litres vs cubic feet for cylinders | Yes, with a table | In the Cylinder Database | No |
| Offline | Needs the page loaded | Yes | Varies |
| Price | Free, no account | Free tool in the app | Free |

## Facts at a glance

- **Page:** https://divekit.app/tools/dive-unit-converter/
- **Modes and units:** pressure (bar, psi, MPa), volume (litres, cubic feet), depth (meters, feet), temperature (°C, °F, K), weight (kg, lb), SRMV/SAC (L/min, bar/min, ft³/min)
- **Defaults:** 200 bar, 12 L, 30 m, 25 °C, 15 kg, 20 L/min; cylinder volume 12.2 L for bar/min
- **Works without an account:** yes; the default result and all reference tables are in the page HTML
- **Same code as the app:** yes, @divekit/core `convertPressureEnhanced`, `convertVolume`, `convertDepth`, `convertTemperature`, `convertWeight`, `convertRMV`
- **In the app:** the Unit Converter is a free tool on iOS and Android, works offline and leaves the app-wide unit setting alone
- **Guide:** https://divekit.app/docs/tools/unit-converter/
- **Limits:** a conversion aid, not a gas planner
- **App Store (iOS):** https://apps.apple.com/app/divekit/id6753089545
- **Google Play (Android):** https://play.google.com/store/apps/details?id=app.skuba.diving
- **Last updated:** 2026-10-30

## Sources

- [NIST Guide to the SI (SP 811), Appendix B.8](https://www.nist.gov/pml/special-publication-811/nist-guide-si-appendix-b-conversion-factors/nist-guide-si-appendix-b8): psi, foot, cubic foot, pound, bar and temperature conversion factors
- [EN 13319:2000](https://knowledge.bsigroup.com/products/diving-accessories-depth-gauges-and-combined-depth-and-time-measuring-devices-functional-and-safety-requirements-test-methods): the depth-gauge standard the default water setting is named after

## Related

- [Scuba cylinder sizes](https://divekit.app/tools/scuba-cylinder-sizes/): water volume, gas capacity and buoyancy of 38 cylinders
- [SAC and RMV calculator](https://divekit.app/tools/sac-rmv-calculator/): measure your breathing rate in L/min and bar/min
- [Gas consumption calculator](https://divekit.app/tools/gas-consumption-calculator/): plan gas in bar or psi