The Short Answer: 2 Inches of Sand, Ordered by the Yard
Most above ground pool manufacturers call for a 2 inch sand base under the liner. You will see 2 to 3 inches quoted all over the place, and anything in that band is fine. Two inches is the standard target and the number most sand charts are built around.
The thing worth understanding before you order is what the sand is actually for. It is not a leveling compound. Sand is there to cushion the liner and give the pool floor a smooth surface with no rocks, roots or hard clods pressing up into the vinyl. Leveling happens in the dirt underneath, before the sand ever comes off the wheelbarrow.
Order by the cubic yard rather than by the ton if you have the choice. Sand weight swings with moisture content, so a ton of damp sand covers less ground than a ton of dry sand. If you order tonnage based on a chart that assumed dry material and your sand has been sitting in a yard through a rainy week, you can end up short. A cubic yard is a measure of space, and the space you need does not change with the weather.
Buy a little extra either way. Sand compacts as you screed and tamp it, some of it ends up outside the bottom track, and some of it disappears into low spots you did not notice. Rounding up to the next half yard is cheap insurance next to paying a second delivery fee for a wheelbarrow load of material.
Key takeaway: for a typical round above ground pool at a 2 inch base, you are usually looking at somewhere between about a yard and three yards of sand. The exact figure depends on your diameter and on whether you are building the cove out of sand or using foam.
Sand Quantity by Pool Diameter at a 2 Inch Base
Here is the math so you can check any number you find, including ours. You need three steps.
- Find the floor area in square feet. For a round pool that is 3.14 times the radius squared, where the radius is half the diameter.
- Multiply by the depth in feet. Two inches is 0.167 feet.
- Divide by 27 to convert cubic feet into cubic yards.
Round pools
Work a 24 foot round pool through it. The radius is 12 feet, so 3.14 times 144 gives roughly 452 square feet of floor. Multiply that by 0.167 feet of depth and you get about 75 cubic feet. Divide by 27 and you land a little under 3 cubic yards. That is why the common answer to how much sand for a 24 ft above ground pool is 3 yards, rounded up from 2.8.
Run the same formula across the common sizes and you get this. These are 2 inch base figures with no sand cove, rounded up to a number you can actually order.
- 12 foot round. About 0.7 cubic yards. Order 1 yard.
- 15 foot round. About 1.1 cubic yards. Order 1.5 yards.
- 18 foot round. About 1.6 cubic yards. Order 2 yards.
- 21 foot round. About 2.1 cubic yards. Order 2.5 yards.
- 24 foot round. About 2.8 cubic yards. Order 3 yards.
- 27 foot round. About 3.5 cubic yards. Order 4 yards.
- 30 foot round. About 4.4 cubic yards. Order 4.5 to 5 yards.
- 33 foot round. About 5.3 cubic yards. Order 5.5 to 6 yards.
Notice how fast this climbs. Going from 24 foot to 30 foot is only six feet of diameter but it is well over a yard and a half more sand, because area grows with the square of the radius. If you are still deciding on pool size, that is worth knowing before you budget the base material.
Oval and rectangular pools
Skip the circle formula and use length times width for the area, then the same two steps. A 12 by 24 oval is close enough to 288 square feet for ordering purposes. Times 0.167 is about 48 cubic feet, divided by 27 is about 1.8 cubic yards, so order 2 yards. Using the rectangle area for an oval slightly overshoots the true footprint, which is exactly the direction you want to be wrong in when you are buying material.
Ovals also usually involve buttresses or a support system on the straight sides, and those supports want to sit on solid ground or on pavers rather than on loose sand. Budget a bit of extra material for backfilling around that hardware once it is set.
If you are using a sand cove
The cove is the angled ramp of material packed against the inside base of the wall. It supports the liner where the floor meets the wall and keeps the liner from being pulled into the sharp corner by thousands of pounds of water. Every above ground pool needs one. The only question is what it is made of.
If you are shaping the cove out of sand, that is additional material on top of the floor number above. On a mid size round pool, budget roughly another yard for the cove. It is a surprising amount of sand for what looks like a small ramp, because it runs the entire circumference of the wall.
Foam cove strips take the place of that sand ramp and are common on modern installs. They peel and stick to the inside of the wall, and they go on fast. This is the single biggest reason two sand charts online for the same pool size will disagree with each other, sometimes by a full yard or more. One is assuming a sand cove and one is assuming foam. Check which one you are reading before you order.
If you would rather not do arithmetic at all, a volume calculator will handle the conversion once you plug in your diameter and depth. Just remember to add the cove yardage yourself if you are going the sand route, since most calculators only give you the flat floor.
Masonry Sand Is the Spec, and Here Is Why
Quantity is only half the order. The other half is asking for the right product, and this is where a lot of first time installs go sideways.
Masonry sand, also sold as mason sand or mortar sand, is what belongs under a vinyl liner. It is washed and screened very fine, with no rocks and no shell fragments. That is the entire point. It screeds flat, holds a smooth surface, and feels good underfoot, which matters because you are going to be standing on it barefoot all summer with nothing but a sheet of vinyl in between.
What to ask for at the yard
Tell whoever is taking your order that you want masonry sand for an above ground pool base, and ask whether it is washed. Those two pieces of information get you the right pile loaded. If a yard tells you they do not carry masonry sand, ask what their finest washed sand is before you settle for whatever is closest to the loader.
Concrete sand is the usual fallback when masonry sand is not available locally. It is coarser and grittier, so it packs harder but leaves a rougher surface, and it occasionally carries small stones. It works. It is just the second choice, and if you use it, spend extra time on the final screed and go over the floor on your hands and knees feeling for anything sharp.
Sands to avoid under a liner
- Coarse or all purpose sand. The generic bagged stuff from a home center often contains sharp particles and small pebbles. Under the weight of a full pool, one sharp edge sitting proud of the surface is exactly what puts a pinhole in a liner.
- Play sand. The texture is actually fine, so it is not wrong on paper. It is just sold in small bags, which makes it an expensive and slow way to cover a pool floor. Covering a 24 foot round means moving a pallet worth of bags.
- Pool filter sand. This is not base sand at all. Filter sand is a graded silica product sized specifically to trap debris inside a filter tank. It belongs in the equipment, not under the liner, and buying enough of it to build a base would be a genuinely painful invoice.
- Whatever is already in the yard. Fill sand and bank sand that has not been washed will have clay, silt and small stones mixed through it. Those stones are the problem.
Getting the Base Right Before the Liner Goes Down
Level the dirt first. This is the one instruction people skip and the one that costs them a season. Sand is not a leveling compound, and if you try to make up a slope with a thick wedge of sand on the low side, the thick side settles more than the thin side and the pool goes out of level within months.
The target is a ground surface that is level across the entire footprint, achieved by cutting down into the high side rather than building up the low side. Built up ground compresses under load. Undisturbed native soil does not. On a sloped yard that means real digging, and it is worth doing properly.
While you are down there, strip the sod and pull the roots and rocks out of the footprint. Grass left under the base decomposes and leaves soft spots that show up later as dips in the pool floor.
Once the ground is level and clean, here is the sequence that gives you a good floor.
- Assemble the bottom track so you know exactly where the perimeter sits, then spread the sand inside it.
- Rake the sand out to an even depth across the whole footprint. A couple of scrap boards cut to length make handy depth guides.
- Dampen the sand lightly with a hose. Damp sand holds a screeded surface. Dry sand shifts under your feet and under the liner, and it will not hold a cove shape at all.
- Tamp or roll it, working systematically so you do not miss areas.
- Do a final pass with a long straight board to knock down ridges and fill hollows, then walk the whole floor barefoot to feel for anything hard you missed.
Some installers add a liner pad or a heavy ground cloth over the packed sand for extra puncture protection and to discourage burrowing insects from tunneling up through the base. It is optional, and it is worth considering if your soil has a lot of stone in it.
Year Two: Plan on Re-Leveling
Sand settles. A pool that reads dead level the day you fill it is frequently a half inch or more off by the following spring, especially in the first year while the base consolidates under the weight of the water. This is normal and it is not a sign you did the install wrong.
The signs to watch for are easy to spot once you know them. A water line that visibly rides higher on one side of the wall than the other. One or two uprights leaning out of plumb. Wrinkles appearing in the liner floor toward the low side. Wall connection plates that no longer sit flush on their pads.
A small out of level condition is mostly cosmetic. A significant one is not. Once the pool is meaningfully off, the wall carries uneven pressure and that is a real structural failure risk, not a looks problem. Do not ignore a pool that is visibly leaning.
The fix for a modest correction is to drain the water down, lift the affected uprights slightly, and shim or re-pack material under the low side pads. Larger corrections mean draining fully, pulling the wall and redoing the base, which is why the prep work up front pays for itself.
You can reduce how much settling happens in the first place. Compact the subgrade before any sand goes down. Keep the sand damp while you pack it so it consolidates now rather than later. Set the uprights on solid pavers or blocks bedded into the soil rather than loose on top of sand. And grade the ground around the pool so roof runoff and downspouts are not discharging toward the base. Water moving through the subgrade is the main thing that turns a level pool into a crooked one.
What This Looks Like on Delivery Day
Bulk sand arrives as a pile, not in packages. Pick your dump spot deliberately, either on the driveway or on a tarp as close to the pool site as a truck can safely get, because every shovelful is moving by wheelbarrow from there.
Plan the labor honestly. A cubic yard of sand is heavy and takes a lot of trips. Two people with two barrows turns this into an afternoon. One person with one barrow turns it into a weekend, and the second half of that weekend is not fun.
Have the footprint fully prepped and the bottom track assembled before the sand shows up. If delivery lands more than a day ahead of install, throw a tarp over the pile. Damp sand is workable and actually easier to screed. Saturated sand that has taken a full rainstorm is miserable to shovel and hard to get to an even depth.
For anything above a very small pool, masonry sand delivered in bulk is almost always noticeably cheaper than the bagged equivalent, and it saves the trips back to the store when you run short at the three quarters mark. That is also the moment the yardage cushion pays off. It is far better to have a small heap of leftover sand for the sandbox than to stop mid install.
How We Started
We started Mulch Mound because we got tired of the hassle that came with buying landscaping materials. The options were either loading bags into your car at a garden center or calling around to local suppliers, trying to figure out pricing, minimums, and delivery schedules. Neither option felt convenient or transparent.
Three of us – Alec, Mo, and Tyler – decided there had to be a better way. Alec and Tyler got their start back in 2013 running a landscaping business during college, moving mulch and mowing lawns to pay tuition. That experience taught them how frustrating it was to source materials, and years later, that frustration turned into Mulch Mound.
We focus on making it simple to get mulch, stone, and soil delivered directly to your home. Order online, pick your delivery date, and we handle the rest. No loading bags. No calling multiple suppliers. No wondering if you bought enough or paid a fair price.
We work with quality local suppliers in the areas we serve and aim to be straightforward about what we offer and what it costs. Landscaping is hard work. Buying the materials for it shouldn't be.
Frequently asked questions
Should I order pool sand by the yard or by the ton?
By the yard when you can. Yards measure space and tons measure weight, and the same pile of sand weighs differently in a dry July than it does after a week of rain. Your pool floor needs a fixed volume of material, so ordering the volume directly removes the guesswork.
Plenty of yards sell only by weight, and that is fine. Just ask them what conversion they use for the sand they are loading that day, so their tonnage and your cubic yard figure are describing the same pile. If they quote you a range, take the heavier end of it for your order.
Can I use play sand under my liner?
The texture is not the problem. The logistics are. Play sand comes in small bags, and a mid size round pool needs enough of them that you are buying by the pallet and hauling them one at a time to the back yard. The cost adds up quickly and the labor adds up faster.
The other catch is consistency. Bagged play sand varies by brand, and some of it carries more fine dust than others, which behaves differently when you dampen and pack it. If bags are genuinely your only option, buy all of it from one brand and one lot so the whole floor behaves the same way.
Do you have to compact the sand before installing the liner?
Yes. Uncompacted sand shifts under the liner as the pool fills and you end up with an uneven floor you cannot fix without draining.
A hand tamper is plenty for a 2 inch layer and costs almost nothing. A rented plate compactor is faster and more consistent on larger pools, and it is genuinely more useful on the subgrade underneath than on the sand itself. A water filled lawn roller is the gentlest option and works well on damp sand. You are not going to over compact a 2 inch layer with any of these, so err toward more passes rather than fewer.
Do I need sand if I am using a liner pad or foam floor padding?
Yes. Pads and foam padding protect the liner from punctures, but they do not smooth anything out. Lay a pad over a lumpy, rocky base and you will feel every one of those lumps through the floor, and the hard spots will still be working against the vinyl from below.
Treat padding as a supplement to a correctly built base, not a substitute for one. The ground still needs to be level, clean and rock free, and the sand still needs to be screeded and packed before anything goes on top of it.
How much sand for an 18 foot round pool?
About 2 cubic yards. The walkthrough is quick. An 18 foot circle has roughly 254 square feet of floor, times 0.167 feet for a 2 inch base is about 42 cubic feet, divided by 27 is 1.6 cubic yards, which you round up to 2 for ordering.
That figure covers the floor only. If you are shaping your cove out of sand rather than using foam strips, add roughly another yard to the order.