Compressed Air Leak Cost Calculator (Free, in AUD)

By Byron Raal, CAS Founder-Editor · Last updated 10 June 2026 · About the author

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The compressed air leak cost calculator quantifies the annual electricity cost in Australian dollars and the carbon abatement available from a single orifice-equivalent leak at a stated hole diameter and line pressure. Inputs include diameter (1 to 10 mm), system pressure (4 to 12 bar), operating hours, electricity rate (approximately $0.30/kWh default), and specific power. Output is dollars per year, kilowatts of compressor load, and tonnes of CO2 emissions per year.

Compressed air leak headline numbers: $276 million a year lost in Australian manufacturing, 25 per cent typical unmanaged leak rate, about $20,250 a year wasted by one 75 kW compressor, leak survey payback under one quarter. — Compressed air leak headline numbers: $276 million a year lost in Australian manufacturing, a 25 per cent typical unmanaged leak rate, and about $20,250 a year wasted by one 75 kW compressor (CAS national leak cost model 2026; US DOE Sourcebook p. 31). Illustrative. Source: Compressed Air Solutions, CC BY 4.0.

How much does a compressed air leak cost?

Area chart showing compressed air leak cost rises with the square of hole diameter, so doubling the hole quadruples the cost. - by Compressed Air Solutions, licensed CC BY 4.0.

Lollipop chart of annual energy wasted by leak rate on a 75 kW compressor, 5% ($4,050) to 25% ($20,250), about $810 per 1%. - by Compressed Air Solutions, licensed CC BY 4.0.

A 3 mm orifice-equivalent leak at 7 bar gauge, 4,000 operating hours per year, $0.30/kWh, 6.5 kW per cubic metre per minute specific power costs approximately $3,420 per year in electricity and emits roughly 7.07 tonnes of CO2 per year against the DCCEEW National Greenhouse Accounts Factors 2025 grid average. A $400 fitting replacement recovers its cost in under two months on this single leak.

A single compressed air leak is small enough to ignore and expensive enough to wreck the maintenance budget. A 3 mm sharp edged orifice leaking continuously at 7 bar gauge wastes about $3,420 per year in electricity at typical Australian industrial conditions, and it does not sleep. The compressor must run longer, at higher loaded percentage, to make up the leaked air. If the leak does not stop, the electricity bill does not stop either. This calculator quantifies that cost in Australian dollars so you can build the business case for leak detection and repair.

Page conventions: all pressures are bar gauge (barg) unless otherwise noted. PSI conversions, where shown, are for reference only.

Most industrial sites have 5 to 30 leaks of this scale or larger at any given time. The sum total of leak costs on a typical never audited Australian industrial site sits in the tens of thousands of dollars per year of pure energy waste, before counting the additional compressor wear, CO₂ emissions, and maintenance burden caused by the higher duty cycle.

All calculations on this page use choked orifice flow per ISO 6358 with discharge coefficient Cd = 0.65 (conservative for sharp edged industrial orifices), referenced to ISO 1217 Annex C standard conditions (20 degrees Celsius, 100 kPa absolute, 0 per cent relative humidity). Default values are set for typical Australian industrial conditions. Adjust them to match your site.

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Leak Cost Calculator

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How This Calculator Works

The calculator models each leak as a sharp edged orifice discharging to atmosphere under choked (sonic) flow conditions. Choked flow occurs when the ratio of upstream absolute pressure to downstream absolute pressure exceeds the critical value of approximately 1.893 for air (ratio of specific heats gamma = 1.4). For a leak discharging to atmosphere (downstream pressure of about 1.013 bar absolute), any upstream gauge pressure above approximately 0.9 bar produces choked flow, so every industrial compressed air system operating above 1 bar gauge satisfies this condition.

The calculation procedure

Step 1. Measure or estimate orifice diameter. A feeler gauge works for visible leaks; ultrasonic leak detectors with calibration tables work for hidden leaks under pressure.

Step 2. Compute orifice area. A = pi multiplied by (d divided by 2) squared, with d in metres. A 3 mm orifice gives A = 7.07 × 10⁻⁶ m².

Step 3. Compute mass flow rate. For choked flow the mass flow is Cd × A × P × C / sqrt(R × T), where Cd = 0.65 (sharp edged orifice), P is absolute upstream pressure, C is the critical flow factor for gamma = 1.4, R is the specific gas constant for air (287 J/kg/K), and T is the absolute upstream temperature (293 K at 20 degrees Celsius).

Step 4. Convert mass flow to FAD. Divide by the ISO 1217 Annex C reference air density (1.188 kg/m³) to get free air delivery in m³/s, then multiply by 60 to express it in m³/min. This is the volumetric flow the compressor must produce to replace the leaked air.

Step 5. Compute power wasted. Multiply FAD (in m³/min) by compressor specific power. The calculator uses 6.5 kW/(m³/min), typical for a modern oil injected rotary screw compressor with VSD; the US Department of Energy typical reference figure is approximately 6.0 kW/(m³/min). Power is then in kW.

Step 6. Compute annual energy and cost. Multiply power (kW) by annual operating hours (typically 4,000 for single shift, 8,000 for 24/7) and by the marginal electricity tariff. The calculator defaults to $0.30/kWh, a typical commercial and industrial reference for the 2025-26 financial year (actual rates vary by state, retailer, and contract).

Step 7. Compute CO₂ emissions. Multiply annual energy (kWh) by the grid emissions factor of 0.62 kg CO₂-e per kWh (Australian national average per DCCEEW NGA Factors 2025 Table 1; state factors range from 0.20 in TAS to 0.78 in VIC). State-specific Scope 2 factors are published by the Department of Climate Change, Energy, the Environment and Water.

Worked example: a 3 mm leak at 7 bar gauge

At the default conditions (3 mm diameter, 7 bar gauge, Cd = 0.65, 4,000 op hr/year, $0.30/kWh, 6.5 kW/(m³/min) specific power), the calculator returns: leak flow approximately 7.31 L/s (0.439 m³/min) FAD, power wasted 2.85 kW, annual energy 11,400 kWh, annual cost $3,420, annual CO₂-e emissions 7.07 tonnes. This matches the most-cited external reference. The US Department of Energy and Compressed Air Challenge orifice data, with its own sharp-edged correction applied, puts a 3 mm leak at roughly 7 to 7.5 L/s, and this calculator returns 7.31 L/s. Tables that quote higher numbers, often 50 percent or more above this, assume a smooth machined nozzle. Real leaks are torn fittings and split hose, not nozzles, so this calculator uses the sharp-edged discharge coefficient and reports the honest figure rather than the flattering one.

Common Leak Sizes and Their Cost

Annual electricity cost of one compressed air leak by hole diameter, 1 mm to 8 mm, at 700 kPa; an 8 mm leak costs 64 times a 1 mm leak. — Annual electricity cost of a single compressed air leak by hole diameter, at 8,000 operating hours per year (continuous 24/7 running), $0.30/kWh and 6.5 kW/(m³/min) specific power, CAS national leak cost model 2026. Source: Compressed Air Solutions, CC BY 4.0.

The table below shows pre-calculated costs for common leak sizes at 7 bar gauge, $0.30/kWh, 4,000 operating hours per year, and 6.5 kW/(m³/min) specific power. These match the calculator’s default output to within rounding.

Leak diameter	Air loss (FAD)	Power wasted	Annual cost	CO₂-e per year
1 mm (pinhole)	0.81 L/s (0.049 m³/min)	0.32 kW	$384	0.79 tonnes
2 mm (fitting leak)	3.25 L/s (0.195 m³/min)	1.27 kW	$1,524	3.15 tonnes
3 mm (coupling leak)	7.31 L/s (0.439 m³/min)	2.85 kW	$3,420	7.07 tonnes
5 mm (worn seal)	20.3 L/s (1.22 m³/min)	7.92 kW	$9,504	19.64 tonnes
10 mm (open valve)	81.3 L/s (4.88 m³/min)	31.7 kW	$38,040	78.64 tonnes

A plant with ten leaks averaging 2 mm in diameter wastes about $15,240 per year in electricity alone. Left un-audited for a decade, that adds up to roughly $150,000 in cumulative energy cost, before counting the knock on effects: longer compressor run hours, accelerated maintenance wear, reduced point of use pressure, and potential production quality impact in pressure sensitive applications.

Leaks Adding Up?

A professional ultrasonic leak survey typically finds 20 to 50 leaks in a medium sized plant and pays for itself within weeks. Compressed Air Solutions can match you with leak detection specialists in your area.

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Why Leak Repair Is the Highest ROI Compressed Air Work

Leak repair isn’t glamorous, but it’s usually the highest ROI compressed air work on any industrial site because the waste stops the moment the fitting seals. Compressed air leak repair has a combination of features that no other energy efficiency project on a compressor system matches.

Cheap to detect. An ultrasonic survey of a medium industrial facility runs $1,500 to $5,000 and finds most detectable leaks in a single visit.
Cheap to fix. Most leaks are joint, fitting, or quick disconnect failures fixed in 5 minutes per leak with a few dollars of parts.
Immediate energy benefit. The repaired leak stops costing money the moment it stops leaking. No commissioning delay, no learning curve.
Persistent benefit. A properly repaired joint stays repaired for years, generating savings continuously.
Verifiable. A post repair blow down test (system pressure decay with all consumers isolated) measures the achieved leak rate reduction directly.

Compare that against other compressed air energy work: a VSD compressor retrofit takes 3 to 12 months from quotation to commissioning; new compressor capital projects can take 12 to 24 months; heat recovery requires engineering design, contractor coordination, and integration with existing plant. Leak repair is the first dollar fix that needs a maintenance day and a competent technician, not a capital expenditure committee. The US Department of Energy Industrial Efficiency and Decarbonization Office and the Compressed Air and Gas Institute both publish best practice guidance treating leak management as the first action item in any compressed air energy programme.

Which Leaks to Fix First

A leak register doesn’t tell you what to fix first unless it ranks dollars, access, and shutdown timing. Survey reports typically list 50 to 200 detected leaks at a single industrial facility. Not all warrant the same urgency. The 80/20 rule applies: the top 10 to 20 per cent of leaks usually represent 60 to 80 per cent of total leak cost.

Tier 1 (immediate fix). Leaks of 3 mm or larger at typical industrial pressures, each costing $3,000 or more per year. These pay back the ultrasonic survey itself within days. Typical count: 5 to 15 leaks per facility.
Tier 2 (next planned shutdown). Leaks in the 2 mm range, each costing $1,000 to $3,000 per year. Schedule the fix for the next planned shutdown when access is convenient. Typical count: 20 to 50 leaks per facility.
Tier 3 (rolling maintenance). Smaller leaks below $1,000 per year (typically 1 mm pinhole class). Roll into routine preventive maintenance and fix tag and fix style during scheduled work. Typical count: 25 to 100 leaks per facility.

Plot the leak cost histogram for any never audited site and the long tail dominates. Fixing the top tier first delivers the bulk of the savings and frees up compressor capacity that can defer the next capital purchase. For plants running rotary screw compressors at high load, a 15 per cent leak rate reduction can shift the operating point enough to justify a smaller replacement unit at end of life.

Building Leak Management Into the Maintenance Programme

A leak programme doesn’t work if it stops at a spreadsheet. A mature compressed air leak management programme on any site with compressor capacity above 22 kW has five elements running in parallel.

Annual ultrasonic survey by an independent provider, producing a full leak register and a cost prioritised repair list.
Quarterly blow down test to verify that the leak rate stays inside budget between major surveys.
Maintenance crew trained on basic leak detection so tagged leaks found during routine work get logged; this tag and fix culture supplements the formal survey cadence.
Documentation of survey results, repair actions, and verification tests in the site’s CMMS or quality management system.
Trend reporting showing year on year leak rate trajectory. A flatlining or rising leak rate signals a culture gap that needs management attention, not just another survey.

Smaller sites can scale the programme down (biennial surveys instead of annual, informal blow down tests) but the underlying principle holds: leaks compound, surveys are cheap, repair pays back quickly. Don’t leave the biggest leaks waiting for a perfect shutdown.

Pressure equipment such as air receivers and pressure piping may be subject to AS/NZS 1200:2015 Pressure Equipment and periodic in-service inspection under AS/NZS 3788:2024 Amd 1:2025 Pressure Equipment In-Service Inspection, depending on the AS 4343:2014 hazard level and the requirements in your jurisdiction. A leak survey fits naturally into the inspection cycle and supports the general duty of care under state and territory work health and safety legislation. Receivers also carry registration obligations depending on their hazard level.

For facilities with pressure sensitive processes such as food and beverage manufacturing or pharmaceutical production, leaks also represent a contamination pathway. A leak in a clean air zone can draw unfiltered ambient air into the system during depressurisation events, potentially compromising product quality.

Frequently Asked Questions

How accurate is this calculator compared to a real leak measurement?

This calculator uses choked orifice flow equations per ISO 6358 with a discharge coefficient of 0.65, conservative for sharp edged industrial orifices typical of failed unions and joint leaks. Real leaks vary depending on orifice shape, edge condition, and upstream turbulence. Expect results within plus or minus 20 per cent of actual values. For precise measurement, an ultrasonic leak detector with flow estimation or a downstream flow meter gives more accurate data.

How much does a single compressed air leak cost in Australia?

At default Australian conditions (7 bar gauge, 4,000 operating hours per year, $0.30 per kWh electricity, 6.5 kW per cubic metre per minute compressor specific power), a 3 mm sharp edged leak wastes approximately $3,420 per year and 7.07 tonnes of CO2-e. A 2 mm leak wastes approximately $1,524, a 5 mm leak approximately $9,504. Use the calculator above to model your specific pressure, hours, and tariff.

Why is leak repair the highest ROI work in a compressed air system?

Leak repair has a unique combination of features that no other compressed air energy work matches. Detection is cheap, with a full ultrasonic survey typically $1,500 to $5,000 for a medium industrial facility. Repair is cheap, with most leaks being joint, fitting, or quick disconnect failures fixed in minutes for a few dollars of parts. The energy benefit is immediate, with savings starting the moment the leak stops. Compare that against a VSD compressor retrofit (3 to 12 months) or new compressor capital (12 to 24 months). Leak repair is the first dollar fix that needs a maintenance day, not a capital expenditure committee.

Which leaks should I fix first?

Survey reports typically list 50 to 200 leaks at a single industrial facility. Not all warrant the same urgency. Tier 1 (immediate fix) covers leaks of 3 mm or larger at typical industrial pressures, each costing $3,000 or more per year. These pay back the survey itself in days. Tier 2 covers 2 mm leaks costing $1,000 to $3,000 per year; schedule for the next planned shutdown. Tier 3 covers smaller leaks under $1,000 per year; roll into routine preventive maintenance. The top 10 to 20 per cent of leaks typically represent 60 to 80 per cent of total leak cost.

Does reducing system pressure reduce leak costs?

Yes. Leak flow rate is directly proportional to absolute upstream pressure under choked flow conditions. Reducing system pressure from 8 bar gauge to 7 bar gauge reduces absolute pressure by about 11 per cent, which reduces leak flow and cost by approximately 11 per cent. Pressure optimisation is one of the fastest energy savings in compressed air systems, with compressor energy savings of about 6 to 7 per cent per bar reduced.

How often should leak surveys be done?

Annual ultrasonic surveys by an independent provider, with quarterly blow down tests in between, is the standard cadence for industrial sites with compressor capacity above 22 kW. Smaller sites can scale this down to biennial surveys with informal blow down testing. The economics consistently support this on any site with serious compressed air consumption: surveys are cheap, the leak rate creeps up between surveys, and a one year gap typically lets enough new leaks form to undo most of the previous round of savings.

Stop Paying for Air You Are Not Using

Compressed Air Solutions connects you with qualified leak detection and compressed air specialists across Australia. Describe your system and we will match you with providers who can survey, quantify, and fix your leaks.

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Related Resources

Compressed Air Audit Australia: quantify and act on the leaks this calculator finds.
Leak detection guide: methods, equipment, and survey programme planning for compressed air leaks.
Energy audit guide: how to assess total compressed air system efficiency and identify savings beyond leaks.
Sizing guide: how to size a compressor and receiver tank correctly so leak load doesn’t drive premature capital decisions.
Dew point calculator: companion calculator for compressed air dryer selection by ISO 8573-1 water class.

Calculator disclaimer. This calculator provides indicative estimates only, based on the inputs you supply and the standard assumptions stated on this page. Results are not a substitute for a site-specific assessment by a qualified engineer. Actual energy use, savings, equipment sizing, and payback depend on factors this tool cannot capture, including your duty cycle, ambient conditions, existing plant, and electricity tariff. Do not make purchasing or capital decisions on these figures alone. Compressed Air Solutions accepts no liability for decisions made on the basis of this tool.

Related: The Hidden Cost of Compressed Air Leaks in Australian Industry (2026) scales these per-leak numbers up to the national picture for Australian manufacturing.