Calcmeister

Compressed air leak cost calculator

Enter the size of the leak, the system pressure and your running hours. The calculator shows what the leak costs you every year.

mm

A leak you can hear clearly is usually 1 to 3 mm.

pcs
bar
h

Leaks lose air whenever the network is pressurised, also at night if the compressor keeps it up.

kW per m³/min

Typical 6 to 7.5 for screw compressors at 7 bar. Found on the compressor data sheet.

per kWh
Cost per year
–
Air loss
– l/s
Wasted power
– kW
Energy per year
– kWh

    How the leak is calculated

    Air escaping through a small hole at normal working pressure reaches the speed of sound in the hole. The flow then depends only on the hole area and the pressure inside the system:

    ṁ = Cd · A · p0 · √(γ ÷ (R T)) · (2 ÷ (γ + 1))(γ+1)/(2(γ−1))

    Wasted power = free air flow (m³/min) · specific power (kW per m³/min)

    The calculator uses a discharge coefficient Cd of 0.9, air at 20 °C, and converts the mass flow to free air at atmospheric pressure.

    What leaks cost

    Hole diameterAir loss at 6 barWasted powerCost per year*
    1 mm1.0 l/s0.4 kWabout 450
    2 mm3.9 l/s1.5 kWabout 1,800
    3 mm8.7 l/s3.4 kWabout 4,100
    5 mm24 l/s9.5 kWabout 11,400
    10 mm97 l/s38 kWabout 45,500

    * 8,000 hours per year, 6.5 kW per m³/min, electricity at 0.15 per kWh. Real leaks are rarely round holes; treat the results as an order of magnitude.

    Where leaks hide

    A leak survey with an ultrasonic detector typically pays for itself within weeks. Repeat it once or twice a year, because new leaks appear constantly.

    Questions and answers

    How much does a compressed air leak cost?

    A single 3 mm leak at 6 bar loses around 9 l/s of free air and wastes about 3.4 kW of compressor power. Running 8,000 hours a year at 0.15 per kWh, that is roughly 4,000 per year.

    How common are leaks?

    Studies of industrial plants regularly find 20 to 30 % of compressed air lost to leaks. Well-maintained systems stay below 10 %.

    How do I find leaks?

    Listen during quiet hours, use soapy water on joints, or use an ultrasonic leak detector, which finds leaks even in noisy halls. Tag each leak and fix them in order of size.

    How can I measure total leakage?

    Switch off all air users while the network stays pressurised and measure how long the compressor runs loaded versus idle. The loaded share times the compressor capacity is the leakage.

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    Last reviewed: 2026-10-14. Results are estimates for planning. Check them before you rely on them for design, purchase or safety decisions.