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How Much Pea Gravel for a 20x16 Patio?

How much pea gravel for a 20x16 patio is a quick volume problem. 320 square feet at 3 inches comes to 2.96 cubic yards. Pea gravel usually weighs about 1.3 to 1.5 tons per cubic yard, so plan on roughly 4.1 tons.

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The math for a 20x16 patio

  1. Area: 20 × 16 = 320 sq ft.
  2. Depth in feet: 3 ÷ 12 = 0.250 ft.
  3. Cubic feet: 320 × 0.250 = 80.0 cu ft.
  4. Cubic yards: ÷ 27 = 2.96 yd³.
  5. Tons: × 1.4 = 4.1 tons.

The volume and tonnage calculator does this for any size.

Pea gravel needed by depth

DepthCubic yardsTons (approx.)Tons +10%
2 in1.982.83.0
3 in2.964.14.6
4 in3.955.56.1

About pea gravel

Pea gravel is small, rounded stone, usually around 3/8 inch. It is comfortable to walk on and drains well, but it shifts under car tires and needs a solid edge to stay put. Weight per yard is a planning number; the scale ticket at the yard is the real one.

Preparing the patio

Remove sod, level the area with a slight slope away from the house, and lay landscape fabric if weeds are a concern. Edging keeps loose material inside the patio footprint. For foot traffic and furniture, the depths in the table above are a reasonable starting range.

Ordering tips

  • Round up. Compaction and uneven ground eat material. Adding about 10 percent is common.
  • Delivery size. 4.6 tons fits in a single typical dump truck load; small loads may carry a delivery fee. See how many tons of gravel in a dump truck.
  • Bulk vs bags. At this size bulk delivery is usually the practical choice.
  • Where it drops. Have the truck dump as close to the patio as firm ground allows.

When to choose pea gravel

Good uses:

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

Think twice 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 20x25 area at 4 inches takes about 8.6 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.
  • Ignoring the base. A thin surface layer over soft soil fails early no matter how much material is on top.
  • Mixing up cubic yards and tons. Yards are volume, tons are weight; convert with the product’s weight per yard.

Questions people ask

How many tons of pea gravel for a 20x16 patio?

About 4.1 tons at 3 inches deep, or 4.6 tons with 10 percent extra.

How many cubic yards is a 20x16 patio at 3 inches?

About 2.96 cubic yards.

How much does a cubic yard of pea gravel weigh?

Usually around 1.3 to 1.5 tons, depending on stone size, fines and moisture.

How deep should pea gravel be for a patio?

The table above shows 2 to 4 inches. Shallower depths suit top dressing; deeper depths suit new installs and heavier use.

How many square feet is 20x16?

320 square feet.

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