Leak Rate Converter — mbar·L/s, Pa·m³/s, Torr·L/s, atm·cc/s & sccm

Leak Rate & Gas Throughput Converter

Convert leak rates and gas loads between every common unit, work out the leak rate from a pressure-rise test, and see how tight your system really is.

Leak rate / throughput

Try:

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Pa·m³/s

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mbar·L/s

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Torr·L/s

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atm·cc/s

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Pa·L/s

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sccm

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slm

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Torr·L/min

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Rate-of-rise leak test calculator

Leak-tightness classes

Typical rule-of-thumb thresholds used in industry (air/helium, mbar·L/s). Always check the specification for your product.

Leak rate (mbar·L/s)	Pa·m³/s	sccm	Tightness	Examples
≤ 0.01	0.001	0.592	Water-tight (droplets)	Plumbing fittings, water tanks
≤ 0.001	1×10⁻⁴	0.0592	Vapour-tight	Sweat-free containers, simple housings
≤ 1×10⁻⁴	1×10⁻⁵	0.00592	Bacteria-tight	Food & pharma packaging, medical devices
≤ 1×10⁻⁵	1×10⁻⁶	5.92×10⁻⁴	Fuel / oil-tight	Fuel system components, gearboxes
≤ 1×10⁻⁶	1×10⁻⁷	5.92×10⁻⁵	Virus-tight	Blood bags, sterile barrier systems
≤ 1×10⁻⁷	1×10⁻⁸	5.92×10⁻⁶	Gas-tight	Refrigeration circuits, airbag inflators, gas valves
≤ 1×10⁻⁹	1×10⁻¹⁰	5.92×10⁻⁸	High-vacuum-tight	HV chambers, sealed sensors
≤ 1×10⁻¹⁰	1×10⁻¹¹	5.92×10⁻⁹	UHV-tight / hermetic	UHV systems, pacemakers, hermetic electronics

Leak rate (mbar·L/s)

Pa·m³/s

sccm

Tightness

Examples

≤ 0.01

0.001

0.592

Water-tight (droplets)

Plumbing fittings, water tanks

≤ 0.001

1×10⁻⁴

0.0592

Vapour-tight

Sweat-free containers, simple housings

≤ 1×10⁻⁴

1×10⁻⁵

0.00592

Bacteria-tight

Food & pharma packaging, medical devices

≤ 1×10⁻⁵

1×10⁻⁶

5.92×10⁻⁴

Fuel / oil-tight

Fuel system components, gearboxes

≤ 1×10⁻⁶

1×10⁻⁷

5.92×10⁻⁵

Virus-tight

Blood bags, sterile barrier systems

≤ 1×10⁻⁷

1×10⁻⁸

5.92×10⁻⁶

Gas-tight

Refrigeration circuits, airbag inflators, gas valves

≤ 1×10⁻⁹

1×10⁻¹⁰

5.92×10⁻⁸

High-vacuum-tight

HV chambers, sealed sensors

≤ 1×10⁻¹⁰

1×10⁻¹¹

5.92×10⁻⁹

UHV-tight / hermetic

UHV systems, pacemakers, hermetic electronics

Leak test methods and sensitivity

Method	Typical minimum detectable leak (mbar·L/s)
Bubble test (immersion)	≈10⁻³ – 10⁻⁴
Pressure decay / rate of rise	≈10⁻² – 10⁻⁵ (volume & time dependent)
Helium sniffer	≈10⁻⁶ – 10⁻⁷
Helium accumulation	≈10⁻⁸
Helium vacuum (spray) method	down to ≈10⁻¹²

Method

Typical minimum detectable leak (mbar·L/s)

Bubble test (immersion)

≈10⁻³ – 10⁻⁴

Pressure decay / rate of rise

≈10⁻² – 10⁻⁵ (volume & time dependent)

Helium sniffer

≈10⁻⁶ – 10⁻⁷

Helium accumulation

≈10⁻⁸

Helium vacuum (spray) method

down to ≈10⁻¹²

Understanding throughput units

A leak rate is a throughput: pressure × volume per time (pV-flow). It is proportional to the number of molecules per second entering the system, which is why it can be expressed in pressure-volume units (mbar·L/s, Pa·m³/s, Torr·L/s) or as a standard volumetric flow (sccm, slm, atm·cc/s). The terms are defined in ISO 20484, the leak-testing vocabulary standard.

1 Pa·m³/s = 10 mbar·L/s = 7.50 Torr·L/s = 9.87 atm·cc/s = 592 sccm

To find the pressure a leak will produce in a pumped system, divide by the effective pumping speed: p = Q / S_eff. A 10⁻⁵ mbar·L/s leak on a 100 L/s turbo pump limits the base pressure to about 10⁻⁷ mbar.

References & further reading

ISO/TC 135. ISO 20484:2017 Non-destructive testing — Leak testing — Vocabulary. International Organization for Standardization (2017). Standard terms and units for leak rates.

ASNT. Leak Testing (LT) — nondestructive testing method. American Society for Nondestructive Testing. Leak testing methods and personnel certification.

NIST. Thermodynamic Metrology Group — pressure and vacuum standards. National Institute of Standards and Technology. US primary standards for pressure, vacuum and leak rate.

K. Jousten (ed.). Handbook of Vacuum Technology, 2nd ed.. Wiley-VCH (2016). Standard reference on gas flow, conductance, pumps and gauges.

Frequently asked questions

How do I convert mbar·L/s to Pa·m³/s?

Divide by 10. 1 mbar·L/s = 100 Pa × 0.001 m³/s = 0.1 Pa·m³/s. Conversely, 1 Pa·m³/s = 10 mbar·L/s.

How do I convert mbar·L/s to sccm?

1 mbar·L/s ≈ 59.2 sccm, and 1 sccm ≈ 0.0169 mbar·L/s. sccm is referenced to standard conditions (1 atm, 0 °C), so this conversion assumes the throughput is expressed at the same temperature basis.

What is a rate-of-rise (pressure rise) leak test?

Isolate the evacuated chamber from the pump and record how fast the pressure rises. The total gas load is Q = V · Δp / Δt. A linear rise indicates a real leak; a rise that flattens out indicates outgassing or virtual leaks (trapped gas) that will eventually reach equilibrium.

What leak rate is considered gas-tight?

As a rule of thumb, a component is considered water-tight at about 10⁻² mbar·L/s, bacteria-tight at 10⁻⁴, and gas-tight at around 10⁻⁷ mbar·L/s or better. High and ultra-high vacuum systems usually require total leak rates below 10⁻⁹ to 10⁻¹⁰ mbar·L/s, which can only be verified with a helium leak detector.

Is 1 atm·cc/s the same as 1 std cc/s?

Numerically they are treated as equivalent in leak testing: 1 atm·cc/s ≈ 1.013 mbar·L/s ≈ 0.1013 Pa·m³/s. Strictly, std cc/s specifies a 0 °C reference temperature.

Leak Rate & Gas Throughput Converter

Rate-of-rise leak test calculator

Leak-tightness classes

Leak test methods and sensitivity

Understanding throughput units

References & further reading

Frequently asked questions

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