Skip to main content
DiveCalc
Dive Planning

Dive Unit Converter

Convert pressure, distance, weight, gas flow, tank volume, and temperature values instantly. Enter a value on either side of each pair and the matching unit updates automatically.

Convert Units

Pressure Conversion

Distance Conversion

Seawater Depth to Absolute Pressure

Weight Conversion

Tank Volume Conversion

Convert tank rated volume (cuft) to water volume (liters) using working pressure.

Gas Flow Conversion (SAC / RMV)

Temperature Conversion

About This Tool

This converter is independent from your saved unit preferences and does not require direction toggles.

Type in PSI or bar, feet or meters, feet of seawater or absolute bar, pounds or kilograms, cubic feet tank rating or liters water volume (with working pressure), liters per minute or cubic feet per minute, and Celsius or Fahrenheit. The paired value updates immediately.

Tank-volume conversion is an ideal-gas estimate from water volume and working pressure. Use the manufacturer's rated capacity when available because real-gas compressibility can change the result.

Conversion Factors
1 bar≈14.5038 psi1\,\text{bar} \approx 14.5038\,\text{psi}
1 m≈3.28084 ft1\,\text{m} \approx 3.28084\,\text{ft}
Pabs=(dft33+1)×1.01325 barP_{\text{abs}} = \left(\frac{d_{\text{ft}}}{33} + 1\right) \times 1.01325\,\text{bar}

Seawater at sea level: 33 ft is one standard atmosphere (1.01325 bar), plus the atmosphere above the surface. 100 ft is about 4.08 bar absolute, or 3.07 bar of water alone. For metres, 10 m of seawater is 1 bar of water pressure.

1 kg≈2.20462 lb1\,\text{kg} \approx 2.20462\,\text{lb}
1 ft3≈28.3168 L1\,\text{ft}^3 \approx 28.3168\,\text{L}
1 ft3/min≈28.3168 L/min1\,\text{ft}^3/\text{min} \approx 28.3168\,\text{L}/\text{min}
Vwater≈Vrated CPworkC=28.3168 L/ft3\begin{aligned} V_{\text{water}} &\approx \frac{V_{\text{rated}} \, C}{P_{\text{work}}} \\ C &= 28.3168\,\text{L}/\text{ft}^3 \end{aligned}

For tank conversion, rated volume is in cubic feet and working pressure is in bar in this ideal-gas approximation.

T∘ ⁣F=95T∘ ⁣C+32T_{^\circ\!F} = \frac{9}{5}T_{^\circ\!C} + 32

Frequently Asked Questions

How do I convert feet of seawater to bar?
Divide the depth in feet by 33 to get atmospheres of water pressure, then multiply by 1.01325 to get bar. That is gauge pressure from the water alone. Add one more atmosphere (1.01325 bar) for the air above the surface to get absolute pressure, which is what gas consumption and partial pressure use.
How many bar is 100 feet of seawater?
At sea level, 100 feet of seawater is about 3.07 bar of water pressure, or about 4.08 bar absolute once the atmosphere at the surface is included.
Is 10 meters of seawater exactly 1 bar?
By definition, 1 meter of seawater (msw) is 0.1 bar, so 10 msw is 1 bar of water pressure and about 2.01 bar absolute. The imperial convention instead treats 33 feet of seawater as one standard atmosphere, so the two systems differ by about 0.5% for the same physical depth. Neither convention models fresh water or altitude.

Related Guides

Gas planning & consumption

Scuba Diving Units: Bar, PSI, Meters, and Feet

Gas planning & consumption

Pressure and ATA Basics for Scuba Divers

Gas planning & consumption

SAC Rate vs RMV: What's the Difference and When to Use Each

Related Diving Tools

Gas Management

Cylinder Capacity Calculator

Dive Planning

Dive SAC Rate Calculator

Dive Planning

Gas Consumption Planner

Want the next tool when it lands?

Get a short note when DiveCalc ships a useful new tool or a meaningful update.

Occasional updates. No spam. Unsubscribe anytime.