Pool Base Sand Calculator
Work out the sand for an above-ground pool base. Enter your pool's diameter and the base depth to get cubic yards, tons and bags — pre-set to 2 inches of sand under an 18 ft round pool.
Sets a typical depth — tweak anything below.
For a 18 ft × 18 ft area at 2 in deep, order about 2.2 cubic yards (2.97 US tons) of sand.
Estimates only. Densities vary by moisture, compaction and supplier — confirm quantities before ordering.
How much sand do I need for a pool base?
For a round pool, the area is π × (diameter ÷ 2)², and the sand volume is that area times the depth. An 18 ft round pool with a 2-inch base needs about 1.6 cubic yards — roughly 2 tons. A 24 ft pool needs about 2.8 cubic yards. Switch the shape above to Circle and enter your pool's diameter, or use the table below for the common sizes. Order a little extra: you'll want spare to fine-tune the level as you screed.
Level matters far more than depth
Two inches of sand is plenty for an above-ground pool, and going deeper does not make it better — it makes it worse. Deep sand is harder to compact evenly, and the pool's weight will find every soft spot. The real job is flat: water finds level even if your base doesn't, so a base that's off by an inch across the pool leaves one side's wall carrying more water than it was designed to, and that's how above-ground pools fail. Screed the sand flat with a board and a level, compact it, and check it in several directions before the liner goes down. A pool holds enough water that you get one chance at this.
What kind of sand for a pool base?
Mason sand, sometimes sold as pool sand or play sand at this fineness. You want fine, clean sand with no stones in it, because anything sharp under the liner is a puncture waiting to happen. Don't use concrete sand or sharp sand — the coarse grit is exactly what you're trying to avoid, even though it's what you'd want under pavers. It's worth asking the yard specifically for pool or mason sand rather than 'sand'.
Do you need sand under an above-ground pool?
You need something, and sand is the traditional answer because it's cheap and screeds flat easily. It cushions the liner from stones and roots and gives a smooth floor underfoot. The alternatives worth knowing: foam pads go over a level base instead of sand and won't wash out, and some installers put the pool on compacted crushed stone with foam or a liner pad on top, which drains better and doesn't shift. Sand's weakness is that it can wash out from under the edge in heavy rain if the pool sits low, so grade the ground away from the pool first.
Sand by pool size (2-inch base)
| Round pool | Area | Sand needed |
|---|---|---|
| 12 ft | 113 sq ft | ≈ 0.7 cu yd · 0.9 tons |
| 15 ft | 177 sq ft | ≈ 1.1 cu yd · 1.4 tons |
| 18 ft | 254 sq ft | ≈ 1.6 cu yd · 2 tons |
| 21 ft | 346 sq ft | ≈ 2.1 cu yd · 2.8 tons |
| 24 ft | 452 sq ft | ≈ 2.8 cu yd · 3.7 tons |
| 27 ft | 573 sq ft | ≈ 3.5 cu yd · 4.6 tons |
| 30 ft | 707 sq ft | ≈ 4.4 cu yd · 5.7 tons |
Before waste. Add ~10% so you have spare to screed level with. Tons assume dry mason sand; wet sand weighs more.
Worked examples
- π × (18 ÷ 2)² = 254 sq ft
- 254 × 2 in (0.17 ft) = 42.4 cu ft
- 42.4 ÷ 27 = 1.57 cubic yards
- × ~1.35 ton/yd³ ≈ 2 tons
- π × (24 ÷ 2)² = 452 sq ft
- 452 × 2 in (0.17 ft) = 75.4 cu ft
- 75.4 ÷ 27 = 2.79 cubic yards
- × ~1.35 ton/yd³ ≈ 3.7 tons
- Oval area ≈ π × 7.5 × 15 = 354 sq ft
- 354 × 2 in (0.17 ft) = 59 cu ft
- 59 ÷ 27 = 2.2 cubic yards
- Enter 354 sq ft in the area field
Common mistakes to avoid
- Chasing depth instead of level. 2 inches is enough. A deep sand base compacts unevenly and the pool's weight finds every soft spot. Flat is what matters — check it in several directions.
- Using sharp or concrete sand. The grit that makes concrete sand good under pavers is exactly what punctures a liner. Ask for mason sand or pool sand.
- Leaving stones under the liner. Anything sharp under a full pool is a slow leak. Clear the ground, then screed clean sand over it.
- Not grading the ground first. If water runs toward the pool, it washes sand out from under the edge. Grade away from the pool before you lay the base.
- Ordering exactly enough. You use extra sand fine-tuning the level as you screed. Order about 10% over so you're not stopping mid-job.
Frequently asked questions
How much sand for an 18 ft round pool?+
About 1.6 cubic yards — roughly 2 tons — for a 2-inch base. A 24 ft pool needs about 2.8 cubic yards, and a 15 ft pool about 1.1. Switch the shape to Circle above and enter your diameter for the exact figure.
How deep should the sand base be under a pool?+
2 inches. Deeper isn't better — it's harder to compact evenly and the pool's weight settles into the soft spots. What actually matters is that the base is dead level, because water finds level whether your base does or not.
What kind of sand goes under an above-ground pool?+
Mason sand — fine and clean, with nothing sharp in it. Don't use concrete or sharp sand: the coarse grit that makes it good under pavers is a puncture risk under a liner.
Do you need sand under an above-ground pool?+
You need a smooth, level cushion of some kind. Sand is the cheap traditional answer and screeds flat easily. Foam pads over a level base are the main alternative and won't wash out; some installers use compacted crushed stone with a pad on top for better drainage.
How many bags of sand for a pool base?+
An 18 ft pool needs about 1.6 cubic yards, which is roughly 85 bags at 0.5 cu ft — so bags are not the way to do this. Any pool over about 12 ft is a bulk delivery job.