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Patio Paver Base Calculator · Free calculator

20x20 Patio Paver Base Calculator

A 20' × 20' paver patio (400 sq ft) needs 5.68 yd³ — about 7.95 tons — of compacted gravel base at 4", plus 1.36 yd³ of bedding sand at 1". Here's every layer, bag count and paver quantity for 20x20.

Quick answer

4" gravel base
5.68 yd³ · 7.95 t
6" gravel base
8.52 yd³ · 11.93 t
1" bedding sand
1.36 yd³ · 74 bags
4x8 pavers (+10%)
1,981
Edge restraint
80 LF
Base rock (bulk) @ 4"
$316

▍Gravel Calculator

Material
ft
in
ft
in
in
Waste Factor
$
L = 20' 0"W = 20' 0"D = 4"
Cubic Yards
5.68yd³
incl. 15% waste · Bulk delivery: order 5.75 yd³
Cubic Feet
153.33ft³
Area
400.0sq ft
Weight
7.95tons
Weight
15,901lbs
Gravel bags needed
  • 0.5 cu ft bag (~50 lb) (0.5 ft³ yield)307

Gravel base for a 20x20 paver patio

400 sq ft, +15% for compaction. Crushed stone / Class II road base ≈ 1.4 tons per yd³.

Base depthUseCubic yardsTons0.5 cu ft bagsBulk est.
4"Patio / walkway (foot traffic)5.68 yd³7.95307$316
6"Patio on clay or in frost zones8.52 yd³11.93460$481
8"Paver driveway (vehicles)11.36 yd³15.90614$633

Sand, pavers & edging for 20x20

ItemQuantityNotes
Bedding sand 1" (concrete sand)1.36 yd³ / 1.83 tons74 × 0.5 cu ft bags
Standard 4" × 8" pavers1,9814.5 per sq ft + 10% cuts
Polymeric joint sand (50 lb)7~60 sq ft per bag
Edge restraint80 LF10 × 8' sections, spikes every 12"
Geotextile fabric441 sq ftextend 6" past edges
Excavation depth @ 4" base7.375"4" base + 1" sand + 2-3/8" paver

How the math works

  1. Area: 20 ft × 20 ft = 400 sq ft
  2. Base volume @ 4": 400 × (4 ÷ 12) = 133.33 cu ft
  3. Add 15% for compaction: 133.33 × 1.15 = 153.33 cu ft = 5.68 yd³
  4. Tons: 5.68 yd³ × 1.4 t/yd³ = 7.95 tons
  5. Sand @ 1": 400 × (1 ÷ 12) × 1.10 = 36.67 cu ft = 1.36 yd³
  6. Pavers: 400 sq ft × 4.5 × 1.10 = 1,981 pavers

Trade pro tips

  • A 20x20 patio (400 sq ft) at 4" base needs about 7.95 tons of base rock — have it dumped on a tarp near the dig.
  • Excavate base depth + 1" sand + paver thickness (2-3/8" for standard pavers).
  • Compact the base in 2" lifts with a plate compactor — one thick lift never gets dense.
  • Screed bedding sand to exactly 1". Thicker sand causes pavers to rut and shift.
  • Use edge restraint on every side not held by a wall or slab, spiked every 12".

Frequently asked questions

How much gravel base do I need for a 20x20 paver patio?

At 4" compacted: 5.68 yd³ (7.95 tons). At 6": 8.52 yd³ (11.93 tons). For a paver driveway at 8": 11.36 yd³ (15.90 tons). All include 15% for compaction.

How much sand do I need for 20x20 pavers?

A 1" bedding layer for 400 sq ft is 36.67 cu ft — 1.36 yd³, about 1.83 tons or 74 bags of 0.5 cu ft sand. Add ~7 bags of polymeric sand for the joints.

How many pavers for a 20x20 patio?

About 1,981 standard 4" × 8" pavers (4.5 per sq ft × 400 sq ft + 10% for cuts). Herringbone and other angled patterns can need 15% extra.

How deep should I dig for a 20x20 paver patio?

About 7-3/8" for a patio: 4" gravel base + 1" sand + 2-3/8" pavers. On clay or in frost zones use a 6" base (about 9-3/8" dig), which takes 8.52 yd³ of gravel for 20x20.