Pool Sand Calculator
Find how much filter sand your pool's sand filter needs, based on its tank diameter, using typical manufacturer capacity figures.
How this calculator works
A sand filter’s capacity is set by the shape and size of its filter tank, not by a formula calculated from the pool’s volume or flow rate. Filter manufacturers publish a typical sand capacity for each standard tank diameter, and this calculator matches your tank’s diameter to that published figure so you know roughly how much sand to buy before you open the tank.
Formula: This calculator matches your filter tank’s diameter to a typical published sand capacity for that size (it does not calculate from a formula, since capacity is set by the filter tank’s shape).
Worked example
- Filter tank diameter: 24 inches
- Typical sand capacity: ≈300 lb
Reference
Typical sand filter capacity by tank diameter
| Tank diameter | Sand needed |
|---|---|
| 16 in | 100 lb |
| 19 in | 150 lb |
| 21 in | 200 lb |
| 24 in | 300 lb |
| 27 in | 400 lb |
| 30 in | 500 lb |
How to use
Find your sand filter tank’s diameter, usually printed on the tank itself or listed in its manual, and match it to the closest size in the reference table. Buy sand in that quantity, but always double-check against your filter’s own spec plate before filling it, since exact capacities can vary slightly between manufacturers even at the same nominal diameter.
A typical planning figure. Always check your filter’s own spec plate or manual for its exact rated sand capacity before filling it.
Frequently asked questions
Where do I find my sand filter's tank diameter?
It's usually printed directly on the filter tank itself, often on a label near the base, or listed in the filter's owner's manual or on the manufacturer's product page. If you can't find it printed anywhere, measuring the tank's outer width gives you a close estimate to match against a standard size.
Why doesn't this calculator use a formula based on my pool's size?
A sand filter's capacity depends entirely on how much space its own tank has for sand, not on how big your pool is. Two different pools could use the exact same filter model and need the exact same amount of sand, so the sand quantity is tied to the filter tank's diameter rather than the pool's volume.
What type of sand goes in a pool filter?
Pool filters use a specific graded silica sand sold as filter sand or #20 pool filter sand, not playground or construction sand. Regular sand is either too fine, which clogs the filter, or too coarse, which lets debris pass through — always use sand labeled specifically for pool filter use.
How often does pool filter sand need to be replaced?
Filter sand doesn't get consumed the way it needs regular topping off — it gradually loses its filtering effectiveness as grains break down and become coated with oils and minerals over years of use. Follow your filter manufacturer's replacement interval recommendation and watch for warning signs like cloudy water or reduced flow despite regular backwashing.
Estimates only. Verify quantities with your supplier before purchasing.