Use the equipment’s stated consumption
Name each item and enter its continuous consumption per item while running, at the pressure the job needs. Use figures at the same reference conditions throughout. If a manual only gives averaged consumption, establish the instantaneous demand before treating that number as a peak requirement.
Quantity is the total number available. Simultaneous quantity is the number you plan to run together. The planner shows that scenario separately from the peak if every listed item runs together. It does not model the timing of bursts or prove that a duty-cycle average meets a peak.
Worked example: 50 CFM now, 70 CFM together
Three tools at 20 CFM each plus one at 10 CFM have an all-tools-together peak of 70 CFM. If two of the 20 CFM tools run with the 10 CFM tool, simultaneous demand is 50 CFM. An explicitly chosen 10% spare allowance makes that scenario 55 CFM. It does not change the underlying demand.
Flow is only one part of sizing
Check the required pressure of every item, the pressure loss to the point of use, air quality and the available power supply. This planner does not infer CFM from motor kW or horsepower. Leakage and downstream pressure losses are not included. Compare with compressor FAD at the required working pressure, not displacement. A positive result is a planning figure, not confirmation that a particular compressor is suitable.
Continue with the air compressor sizing guide for the wider hire checklist.