Calculation reviewed: 4 October 2026 · Engineering Desk Tools
How to use the Compressed air receiver size calculator
Size an air receiver to supply a peak demand for a set time within an allowable pressure drop. Start with measurements or documented values for the equipment and reporting period you actually want to assess. The calculator does not fill in a typical installation for you. Its blank fields help keep a demonstration value from being mistaken for your own operating data.
Choose the required options, enter the values in the labelled units and select Calculate. If a field is rejected, check its range and unit before changing it. The result is accompanied by the equation and assumptions so you can decide whether it answers your engineering question.
Inputs and measurement basis
- Demand above compressor output (m³/min free air). Peak demand minus compressor output, in free-air m³/min.
- Duration of the demand event (minutes). How long the peak demand lasts, in minutes.
- Allowable pressure drop in the receiver (bar). Difference between the compressor loading pressure and the lowest acceptable pressure, in bar. The value must be greater than zero.
Record the measurement source and operating condition. Retain unrounded values for verification.
Method and interpretation
A receiver stores compressed air so that a short peak demand can be met without the line pressure falling below the minimum the process needs. The stored volume must supply the shortfall flow for the event duration. Because the usable pressure drop is small compared with the compression ratio, the free air delivered relates to the vessel volume through the allowable drop.
Receiver volume (m³) = shortfall flow × time × atmospheric pressure / allowable pressure drop. Atmospheric pressure is taken as 1.01325 bar.
The flow is the demand that the compressor cannot supply during the event, in free-air units. The pressure drop is the usable difference between the compressor loading pressure and the minimum pressure the process needs. The calculation assumes constant temperature (isothermal) and does not size for compressor control, cycling or leakage. Add margin and confirm the receiver pressure rating, drain and relief requirements.
Worked example
This example does not populate the form. Enter your own installation data.
Calculated result: 12,159 litres receiver volume. Estimated storage for the stated event. Choose the next larger standard vessel and confirm its pressure rating and safety devices.
Check the arithmetic independently using the displayed equation. Retain intermediate precision and compare the final value with your equipment documentation.
Quick-reference table
These illustrative rows retain the worked example assumptions except for the varied input. They are not certified ratings or manufacturer data. Use the form for intermediate values.
Common mistakes
Using demand in actual cubic metres instead of free-air units; counting the full supply pressure as usable instead of the allowable drop; ignoring that loading and unloading pressures set the usable band; undersizing for leakage and long dead-end pipework. Before relying on the output, check the decimal format, unit scale and source of each value. Recheck unusual results against the formula.
Frequently asked questions
Are the example values used automatically?
No. Inputs remain blank when the tool opens or when you clear them. The worked example and table are reading material below the calculator. Enter the actual values you want to check each time, and label saved reports so their context is not lost.
What does the result mean?
The result is the receiver volume that can supply the shortfall for the stated time without the pressure falling more than allowed. Round up to the next standard vessel and add margin.
Can I use a zero or a negative value?
The allowed range follows the meaning of each input. A divisor needs a positive value; other fields may allow zero. Check the form labels and error message rather than forcing an invalid value. A rejected input must be corrected before a result can be shown.
Is this a final design or equipment approval?
No. The flow is the demand that the compressor cannot supply during the event, in free-air units. The pressure drop is the usable difference between the compressor loading pressure and the minimum pressure the process needs. The calculation assumes constant temperature (isothermal) and does not size for compressor control, cycling or leakage. Add margin and confirm the receiver pressure rating, drain and relief requirements. Use the calculation as support for a checked decision, and review equipment documentation and applicable requirements before changing an installation or operating setting.
How can I save or share a calculation?
Calculate first, then use Copy result or Print report. Some maintenance tools also provide a CSV summary. Reports contain your own entered data, so review them before sharing. You can share the public page URL without including plant records or confidential measurements.
How do I report an unexpected result?
Use the Contact page and include the tool URL, input values, units, expected output and the reference you used. Explain the measurement basis. Exclude confidential information.
Related tools and records
Use related calculations with consistent units, periods and equipment scope.
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