Bags of Pea Gravel for a 20x24 Patio

How many bags of pea gravel for a 20x24 patio: at 3 inches deep you need about 120.0 cubic feet, which is 240 bags of the common 0.5 cubic foot size. If your store sells pea gravel in 50-pound bags instead, figure about 249 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	40.0	80	83
2 in	80.0	160	166
3 in	120.0	240	249
4 in	160.0	320	332

How to figure it

Area: 20 × 24 = 480 sq ft.
Volume: 480 × (3 ÷ 12) = 120.0 cu ft.
Bags: 120.0 ÷ 0.5 = 240 bags (round up).

Bags or bulk?

A cubic yard is 27 cubic feet, so 120.0 cubic feet is 4.44 yards, about 6.2 tons. At this size, a bulk delivery usually beats a cart full of bags once you count trips. Compare the bag price × 240 against a bulk quote for 6.8 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.

Before you spread 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.

Good and poor uses for pea gravel

Good uses:

Patios, walkways and dog runs
Play areas with proper depth and edging
Drainage around foundations when sized properly

Less suited to:

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 20x25 area at 4 inches takes about 8.6 tons.
Weight used here: about 1.4 tons per cubic yard.

Where estimates go wrong

Assuming every supplier uses the same weight. Two yards selling the same product name can quote different tons per yard.
Using inches as if they were feet. Depth has to be divided by 12 before you multiply; skipping that step inflates the order twelvefold.
Ordering exactly the math. Uneven ground and spillage nearly always need a little more than the flat calculation.
Measuring only the main rectangle. Aprons, turnouts and curved edges add real square footage.

Questions people ask

How many bags of pea gravel for a 20x24 patio?

About 240 bags of 0.5 cubic feet at 3 inches deep.

How many 50 lb bags of pea gravel for 20x24?

About 249 bags at 3 inches.

How many 0.5 cubic foot bags are in a cubic yard?

54 bags.

How many cubic feet is a 20x24 patio at 3 inches?

About 120.0 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.

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