Engineering CalculationCompressed Air Leakage Test Calculator (on-load / off-load method)
Measure how much compressed air your plant loses through leaks with the simple on-load / off-load test when no air is being used, and see what it costs.
Open the calculator →Formula
Leakage % = T / (T + t) × 100
Leakage quantity = compressor capacity × T / (T + t)
T = on-load time, t = off-load time (with all users closed)
Worked example
Compressor 500 cfm, on-load 20 s, off-load 60 s
Leakage = 20 / (20 + 60) × 100 = 25 % = 125 cfm
Where engineers use it
- Energy audits
- Weekly utility checks
- Air-jet loom and pneumatic plants
How to use
- Click Open the calculator. It runs free in your browser, on desktop or phone.
- Enter your values. Units and typical ranges are shown next to each input.
- Read the result and the step-by-step working, then print or add it to your Project BOQ.
Questions
How do I get cost per year?
Enter the compressor kW, running hours and energy rate; the tool converts leakage to kWh and rupees.