Size air cycles for garden sprayers and pneumatics. Compare fill and runtime quickly. Make better choices with clear pressure and flow inputs.
| Scenario | Tank | From - To (psi) | Compressor (SCFM) | Demand (SCFM) | What to expect |
|---|---|---|---|---|---|
| Portable blowout | 20 gal | 120 - 90 | 5.0 | 8.0 | Runtime is limited; pressure drops steadily. |
| Small sprayer bursts | 6 gal | 110 - 90 | 2.8 | 1.5 | Supply can cover demand; tank refills between bursts. |
| Refill between beds | 30 gal | 90 - 125 | 6.5 | - | Fill time depends mainly on SCFM and pressure rise. |
Use your own tool ratings for better accuracy.
The calculator converts tank size to cubic feet, then estimates stored air using an ideal-gas relationship. Gauge pressure is converted to absolute pressure by adding atmospheric pressure.
Many compressors deliver less air at higher pressures. If you have a performance chart, use the SCFM near your working range.
Compressed air supports garden sprayers, aerators, pneumatic pruners, and winterization blowouts. Knowing how long pressure lasts prevents weak tool performance, uneven application, and repeated stops that waste labor. Tank time planning also reduces overheating by matching work bursts to realistic refill cycles and cooling pauses.
Tank size sets the air reservoir, while the pressure range defines how much usable air sits between your start and stop points. Free-air delivery in SCFM is the compressor’s true output, and it commonly drops as pressure climbs. Duty cycle models practical limits by converting continuous run minutes into elapsed minutes, reflecting thermal protection and motor rest.
Use fill mode when you refill a portable tank at the shop, then work across beds or irrigation zones. A larger pressure rise requires more standard cubic feet, so the same compressor takes longer as the target increases. If you operate from a generator, fill estimates help size electrical load, runtime, and fuel, improving scheduling and safety. For mobile work, note that long hoses and small fittings add restriction, increasing demand and shortening runtime, especially at lower pressures in practice.
Runtime mode compares tool demand against average compressor supply. When demand exceeds supply, the tank makes up the difference and pressure falls predictably. When supply meets demand, pressure holds and the tank becomes a buffer for short peaks. Add leak margin for couplers, hoses, and quick-connects, and use the tool’s rated SCFM at working pressure, not at zero load.
Treat calculated times as planning numbers, then validate with a short trial in the same hose length and nozzle setting. Stop before your minimum usable pressure to protect regulators and maintain consistent spray patterns. For sensitive tasks, keep a wider pressure band and reduce demand with smaller nozzles or shorter bursts. Regularly drain condensate, inspect filters, and confirm relief valves and check valves operate correctly.
Use fill mode when estimating how long it takes to raise tank pressure. Use runtime mode when a tool draws air and you want minutes until pressure reaches your stop point.
Use the free-air delivery rating close to your working pressure. If only one rating is listed, choose the value at 90 psi, or use a conservative estimate for safety.
Duty cycle limits how long the compressor can run continuously. The calculator converts required run minutes into elapsed minutes by adding cooling time, which is useful for heat management.
If average supply meets or exceeds demand, the tank will hold pressure or recharge during use. The runtime result will indicate that demand is covered, and the tank acts as a buffer for peaks.
Small leaks can be significant over minutes. Add a leak margin to cover couplers, cracked hoses, and fittings. Fix leaks to improve runtime and reduce compressor cycling.
It is a planning estimate based on ideal-gas behavior. Real output varies with pressure, temperature, and restrictions. Run a short test at your settings and adjust inputs to match field performance.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.