Bags of Sand for a 20x18 Patio
How many bags of sand for a 20x18 patio: at 2 inches deep you need about 60.0 cubic feet, which is 120 bags of the common 0.5 cubic foot size. If your store sells sand in 50-pound bags instead, figure about 120 bags, since sand weighs roughly 100 pounds per cubic foot.
Volume and tonnage calculator →Bag count by depth
| Depth | Cubic feet | 0.5 cu ft bags | 50 lb bags (approx.) |
|---|---|---|---|
| 1 in | 30.0 | 60 | 60 |
| 2 in | 60.0 | 120 | 120 |
| 3 in | 90.0 | 180 | 180 |
| 4 in | 120.0 | 240 | 240 |
How to figure it
- Area: 20 × 18 = 360 sq ft.
- Volume: 360 × (2 ÷ 12) = 60.0 cu ft.
- Bags: 60.0 ÷ 0.5 = 120 bags (round up).
Bags or bulk?
A cubic yard is 27 cubic feet, so 60.0 cubic feet is 2.22 yards, about 3.0 tons. At this size, a bulk delivery usually beats a cart full of bags once you count trips. Compare the bag price × 120 against a bulk quote for 3.3 tons delivered.
About sand
For paver bedding, concrete sand (coarse, washed) is the usual pick. Mason sand is finer and used in mortar and play areas.
Install tips for a patio
- Dig and level. Remove sod and set the base slightly below the surrounding grade.
- Edge it. Steel, plastic or stone edging keeps material in place.
- Spread in layers. Rake to depth, then tamp or wet and compact.
- Buy a few extra. Grab 5 to 10 percent more bags for settling and touch-ups.
The volume and tonnage calculator handles other sizes and depths.
Where sand fits
Good uses:
- Paver and flagstone bedding
- Leveling under above-ground pools (with the right product)
- Filling joints and backfilling pipe
Less suited to:
- Driveway bases, since sand shifts under load
- Steep areas exposed to runoff
- Thick layers under pavers, which settle unevenly
Quick reference numbers
- Per inch over 100 sq ft: about 0.42 tons of sand (0.31 cubic yards).
- Per inch over 1,000 sq ft: about 4.2 tons.
- Another size for comparison: a 10x20 area at 4 inches takes about 3.3 tons.
- Weight used here: about 1.35 tons per cubic yard.
Mistakes that throw off the order
- Forgetting that compaction shrinks loose material. A loose 4-inch spread of a dense-graded stone may finish closer to 3 inches after rolling.
- Mixing up cubic yards and tons. Yards are volume, tons are weight; convert with the product’s weight per yard.
- Ordering exactly the math. Uneven ground and spillage nearly always need a little more than the flat calculation.
- Skipping drainage. Water sitting under any surface softens the base and leads to ruts and potholes.
Questions people ask
How many bags of sand for a 20x18 patio?
About 120 bags of 0.5 cubic feet at 2 inches deep.
How many 50 lb bags of sand for 20x18?
About 120 bags at 2 inches.
How many 0.5 cubic foot bags are in a cubic yard?
54 bags.
How many cubic feet is a 20x18 patio at 2 inches?
About 60.0 cubic feet.
When does bulk make more sense?
Usually once the job passes about a cubic yard, or when you would need more than a few car trips.
Related guides
- How Much Does a Ton of Sand Cover?
- Tons to Cubic Yards for Gravel: Conversion Chart
- How Much Does a Ton of Gravel Cover? Depth Chart
- Bags of Sand for a 20x14 Patio
- Bags of Sand for a 20x16 Patio
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