Pressure Tank Size Calculator
Estimate required water-system drawdown, nominal storage capacity, selected tank quantity, purchased volume and cost.
Default project preview
55 gal
Required usable water
16.5 gal
Selected tanks
2
Purchased nominal volume
88 gal
Purchased usable water
26.4 gal
Calculator
Build the material order
Your order will appear here
Enter the project details and calculate a rounded material estimate.
Methodology
Transparent calculation
BuildMeter converts every input to a consistent internal unit, applies the selected allowance, and rounds products up to whole purchasable units.
Required usable water = pump flow × minimum runtime × reserve factor. Required nominal capacity = usable water ÷ entered usable fraction.
FAQ
Pressure Tank Size Calculator questions
Why is nominal capacity larger than usable water?+
Only part of the rated tank volume is delivered during a normal operating cycle.
Can multiple smaller tanks be combined?+
Often yes, when the piping and controls are designed for parallel tanks.
Where should the usable fraction come from?+
Use the selected manufacturer’s published drawdown data for the operating settings.