Bags of Pea Gravel for a 20x20 Patio
How many bags of pea gravel for a 20x20 patio: at 3 inches deep you need about 100.0 cubic feet, which is 200 bags of the common 0.5 cubic foot size. If your store sells pea gravel in 50-pound bags instead, figure about 208 bags, since pea gravel weighs roughly 104 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 | 33.3 | 67 | 70 |
| 2 in | 66.7 | 134 | 139 |
| 3 in | 100.0 | 200 | 208 |
| 4 in | 133.3 | 267 | 277 |
How to figure it
- Area: 20 × 20 = 400 sq ft.
- Volume: 400 × (3 ÷ 12) = 100.0 cu ft.
- Bags: 100.0 ÷ 0.5 = 200 bags (round up).
Bags or bulk?
A cubic yard is 27 cubic feet, so 100.0 cubic feet is 3.70 yards, about 5.2 tons. Past about a yard, bulk is usually less work and often less money. Compare the bag price × 200 against a bulk quote for 5.7 tons delivered.
About pea gravel
Because pea gravel is round, it never fully locks. Keep depths modest on walkways and patios so it does not feel like walking on a beach, and use edging.
Laying it down 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 rake smooth; rounded stone will not 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 pea gravel fits
Good uses:
- Patios, walkways and dog runs
- Play areas with proper depth and edging
- Drainage around foundations when sized properly
Poor fit for:
- Driveways and steep paths, where it rolls and ruts
- Under pavers as a base
- Areas without edging
Quick reference numbers
- Per inch over 100 sq ft: about 0.43 tons of pea gravel (0.31 cubic yards).
- Per inch over 1,000 sq ft: about 4.3 tons.
- Another size for comparison: a 8x16 area at 2 inches takes about 1.1 tons.
- Weight used here: about 1.4 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.
- Skipping drainage. Water sitting under any surface softens the base and leads to ruts and potholes.
- Assuming every supplier uses the same weight. Two yards selling the same product name can quote different tons per yard.
- Ordering exactly the math. Uneven ground and spillage nearly always need a little more than the flat calculation.
Questions people ask
How many bags of pea gravel for a 20x20 patio?
About 200 bags of 0.5 cubic feet at 3 inches deep.
How many 50 lb bags of pea gravel for 20x20?
About 208 bags at 3 inches.
How many 0.5 cubic foot bags are in a cubic yard?
54 bags.
How many cubic feet is a 20x20 patio at 3 inches?
About 100.0 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 Gravel Cover? Depth Chart
- Tons to Cubic Yards for Gravel: Conversion Chart
- How Much Does a Ton of Gravel Cover? Depth Chart
- Bags of Pea Gravel for a 20x16 Patio
- Bags of Pea Gravel for a 20x18 Patio
As an Amazon Associate, AsphaltTons.com earns from qualifying purchases. Product links below are sponsored.