Estimate gallons for a common backyard pool
Rectangle pool
Inputs
- 16 ft length
- 32 ft width
- 4.5 ft average depth
About 17,235 gallons.
Use average depth, not maximum depth, when the pool has a shallow and deep end.
Volume calculator
Estimate pool volume before adding salt.
Pool volume is the base input for every salt calculation. A small volume error can turn into a large salt error, so measure length, width, diameter, and average depth as carefully as practical.
Calculator
Pool salt calculator
Auto-calculates as you type.
Volume input
Use average depth for pools with a shallow and deep end. For unusual shapes, split the pool into simpler sections and add the estimates.
Calculator
Pool volume calculator
Estimate gallons before adding salt.
Calculator
Pool salt dilution calculator
Estimate drain and refill volume.
Salt overflow mode
Result examples
See the kind of output this tool produces.
These curated examples make the calculator result easier to understand before you enter your own pool reading.
Estimate gallons before adding salt
Round pool
Inputs
- 24 ft diameter
- 4 ft average depth
About 13,535 gallons.
Round-pool volume uses radius squared, so measuring diameter accurately matters.
Estimate a non-rectangular pool
Oval pool
Inputs
- 30 ft length
- 15 ft width
- 4 ft average depth
About 10,576 gallons.
For unusual shapes, split the pool into sections and add the estimates.
Rectangle
Length x width x average depth x 7.48052
Round
Pi x radius squared x average depth x 7.48052
Oval
Pi x half length x half width x average depth x 7.48052
Measurement notes
- Use average depth when the pool has a shallow and deep end.
- For metric dimensions, convert cubic meters to gallons before salt calculation.
- For unusual shapes, split the pool into simpler sections and add the estimates.
Pool volume FAQ
How do I calculate pool volume in gallons?
Choose the pool shape, enter the measured dimensions, and use average depth. The calculator converts the cubic volume into gallons so the salt calculator can use the same volume basis.
Should I use shallow depth or deep depth for pool volume?
Use average depth when the pool has both shallow and deep areas. A practical average gives a safer salt estimate than using only the deepest or shallowest point.
Can I use metric measurements for pool volume?
Yes. Metric dimensions are converted through cubic meters and then into gallons for salt calculations. The result keeps the workflow consistent for both metric and imperial users.