# Scuba Tank Sizes and Cylinder Chart (Dive Kit): AL80, HP100 and Steel Cylinders

_Last updated: 2026-10-30_

> A free scuba tank sizes chart at https://divekit.app/tools/scuba-cylinder-sizes/ for 38 common scuba cylinders (AL80, AL100, HP100, LP85, steel 12 L and 15 L, CCR cylinders and more): water volume, working pressure, real-gas capacity in litres and cubic feet, empty weight, and buoyancy full, at 50 bar and empty. Pick one for its spec sheet or sort the full chart. It runs the same @divekit/core code and open dataset as the Dive Kit app's Cylinder Database. Free, no account.

## Who is the scuba cylinder sizes page best for?

- **Divers renting unfamiliar cylinders** on a trip who want the specs before they splash.
- **Divers comparing cylinders**, such as HP100 against AL80, or a steel 12 L against a 15 L: gas, weight and buoyancy side by side.
- **Divers moving between metric and US naming**: the page shows why an AL80 is 11.1 L and about 77 ft³ at the same time.
- **Weighting and gas planning**: the same figures feed Dive Kit's weight and gas calculators.

## Formula

```latex
V_\text{gas} = \frac{V_\text{water} \times p_\text{work}}{Z(p_\text{work}, T) \times 1.01325}
```

V_water is the water volume in litres, p_work the working pressure in bar, 1.01325 bar one atmosphere. Z is the compressibility factor of air from NIST reference data: at 15 °C (EN/ISO) for the metric figure, at 70 °F (the true-capacity convention of Luxfer and Faber HP spec sheets) for the figure in cubic feet. With Z = 1 it is the ideal-gas sum behind most marketed names.

## How does Dive Kit compute it?

- Water volume, working pressure, empty weight and buoyancy come from the Dive Kit open cylinder dataset (38 cylinders, MIT licence, https://open.divekit.app/datasets/cylinders.json).
- Gas capacity is computed with real-gas compressibility, not stored. Metric shows whole litres of free gas contained at 15 °C; imperial shows tenths of a cubic foot at 70 °F, so it can be set beside a manufacturer's chart.
- Worked example (computed by the page at build time): an AL80 (11.1 L, 3000 psi) is 80 ft³ by the ideal-gas sum, 77.4 ft³ with real gas at 70 °F (Luxfer's published figure) and 2,204 L at 15 °C.
- In imperial, a cylinder with a marketed rating shows it beside the computed capacity ("Rated 80 cu ft is the marketed name").
- AL80 FAQ figures (computed at build time from the dataset with core): about 14.3 kg (31.5 lb) empty without a valve; at 20 L/min SRMV and 18 m (59 ft) a full AL80 reaches a rule-of-thirds reserve after about 25 minutes and is empty after 39 minutes, time at that depth only.
- Buoyancy is the cylinder alone in water with its valve, without regulator, bands or rigging, signed to one decimal with Floats or Sinks.
- The chart is sortable by every column and filterable by material (aluminum, steel).

## How does it compare?

| | Dive Kit web page | Dive Kit app (Cylinder Database) | Manufacturer spec sheet | Typical tank chart online |
|---|---|---|---|---|
| Cylinders | 38, several makers | Same 38, with search and filters | One maker's range | Varies |
| Gas capacity | Real gas, 15 °C and 70 °F | Same | Maker's convention | Usually the marketed name |
| Buoyancy full / 50 bar / empty | Yes | Yes | Often full and empty | Sometimes |
| Open data | Yes, MIT licence | Same dataset | No | Rarely |
| Price | Free, no account | Free tool in the app | Free | Free |

## Facts at a glance

- **Page:** https://divekit.app/tools/scuba-cylinder-sizes/
- **Per cylinder:** water volume, working pressure, gas capacity (litres at 15 °C, ft³ at 70 °F), marketed ft³ rating where one exists, material, empty weight, buoyancy full / 50 bar / empty, typical use, common brands, notes
- **Coverage:** 38 aluminium and steel cylinders, AL13 to Steel 18L 232 by water volume, including CCR cylinders
- **Units:** metric and imperial toggle on the spec sheet; the chart shows bar and psi, litres and ft³
- **Works without an account:** yes; the default spec sheet and the full chart are in the page HTML
- **Same code as the app:** yes, @divekit/core `freeGasCapacityLitres` and `usRatedCapacityLitres`
- **Open data:** https://open.divekit.app/datasets/cylinders.json, versioned JSON with a JSON Schema, MIT licence; credit Project Dive Kit with a link to divekit.app
- **In the app:** the Cylinder Database adds fuzzy search by name, use or brand, size and pressure filters, and feeds the gas planner, blender and buoyancy calculator; free on iOS and Android, works offline
- **Guide:** https://divekit.app/docs/tools/cylinders/
- **Limits:** representative values per cylinder type; a given cylinder differs with maker, valve and hardware
- **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

- [Dive Kit open cylinder dataset](https://open.divekit.app/datasets/cylinders.json) (MIT licence): water volume, working pressure, weight and buoyancy
- [Luxfer aluminum cylinder specifications](https://static1.squarespace.com/static/55031996e4b0562b390e52e4/t/5dd593f1f20d1d4b14f41999/1574278157284/Luxfer-Cylinder-Spec-Sheet.pdf): AL80 true capacity 77.4 cu ft; buoyancy quoted with the valve
- [Faber FXG HP cylinder specifications](https://cdn.shopify.com/s/files/1/0287/0699/6329/files/FABER_FXG_SPECS2.pdf): HP100 101.3 cu ft at 3442 psi; −0.59 lb at 500 psi
- [NIST Chemistry WebBook, fluid properties](https://webbook.nist.gov/chemistry/fluid/): density data behind the compressibility factor Z
- [Cylinder capacity explained](https://divekit.app/blog/cylinder-capacity/): the two capacity conventions with worked numbers

## Related

- [Gas consumption calculator](https://divekit.app/tools/gas-consumption-calculator/): how long a cylinder lasts at depth
- [Scuba weight calculator](https://divekit.app/tools/scuba-weight-calculator/): weighting that uses these buoyancy figures
- [Dive unit converter](https://divekit.app/tools/dive-unit-converter/): bar and psi, litres and cubic feet