ToolwickHow to Use This Paver Patio Calculator
Enter the patio length and width in feet, then pick a project type to set the base depth, or type your own. Add the sand depth (1 in is standard), how far the base extends past the patio edge, and your paver length, width, thickness and joint width. Press Calculate materials to see the gravel and sand in tons, the paver count with waste, the polymeric sand in 50-lb bags, a cost estimate, and a table comparing base depths.
Why This Matters
A paver patio is only as good as what's under it. Most failures, such as sunken corners, rocking pavers, or ponding water, come from a thin, poorly compacted base rather than the pavers themselves. In freeze-thaw regions, water in the soil expands and heaves a shallow base, and a patio that looked perfect in October can ripple by spring.
The quantities are larger than most people expect. A 20×15 ft patio is only 300 sq ft, but with a 6 in compacted base that extends 6 in past each edge it needs roughly 10 tons of gravel, about 1.25 tons of bedding sand and over 600 pavers. At $30 per ton for gravel, the base alone is around $300 before delivery fees, which often add $50–$150 per load.
Ordering by the ton is how most suppliers sell base and sand, so converting cubic feet to tons accurately keeps you from paying for a second delivery or hauling away a leftover pile. Homeowners use it to budget a weekend project, and contractors use it to compare quotes and confirm that a bid includes enough base.
How It's Calculated
The calculator works in cubic feet, converts to cubic yards, then to tons using typical bulk densities.
Gravel tons = footprint × depth/12 ÷ 27 × 1.15 × 1.4
Sand tons = L × W × depth/12 ÷ 27 × 1.35
Pavers per sq ft = 144 ÷ ((paver L + joint) × (paver W + joint))
Pavers to order = area × pavers per sq ft × (1 + waste%)
- 1.15 is a compaction allowance. Gravel is delivered loose and shrinks roughly 10–20% when compacted, so you order more than the finished volume.
- 1.4 tons per cubic yard is a typical loose density for crushed stone base (about 2,800 lb). 1.35 is typical for coarse bedding sand. Ask your supplier for their figure.
- Polymeric sand is estimated from joint volume: the joint area per square foot, times the joint depth (paver thickness minus 1/8 in), times 95 lb per cubic foot, plus 20% for sweeping loss. The result is rounded up to whole 50-lb bags.
- Rounding is always up: gravel and sand to the next quarter ton, pavers and bags to whole units.
Worked Example
Patio 20 ft × 15 ft, 6 in base, 1 in sand, 6 in overhang, 12×6 in pavers, 2.375 in thick, 1/4 in joints, 10% waste, gravel $30/ton, sand $35/ton, pavers $4.50/sq ft.
- Area: 20 × 15 = 300 sq ft. The base footprint is 21 × 16 = 336 sq ft (6 in = 0.5 ft added to each side).
- Gravel: 336 × 0.5 ft = 168 cu ft = 6.22 cu yd compacted. × 1.15 = 7.16 cu yd loose. × 1.4 = 10.02 tons, rounded up to 10.25 tons ($307.50).
- Sand: 300 × 1/12 = 25 cu ft = 0.93 cu yd × 1.35 = 1.25 tons ($43.75).
- Pavers: (12.25 × 6.25) = 76.56 sq in each, so 144 ÷ 76.56 = 1.88 per sq ft. 300 × 1.88 = 564.2, so 565 pavers with no waste. With 10% waste: 621 pavers. Cost: 300 × 1.10 × $4.50 = $1,485.00.
- Polymeric sand: joints cover about 8.58 sq in per sq ft, 2.25 in deep, giving 3.35 cu ft over the patio, about 318 lb. Add 20% for 382 lb, or 8 bags of 50 lb.
- Total (gravel + sand + pavers): $307.50 + $43.75 + $1,485.00 = $1,836.25, before delivery, edge restraint, fabric and polymeric sand.
Tips & Common Mistakes
- Compact in lifts of 4 in or less. A plate compactor can't reach through a thick pile, so a 6 in base takes two passes, and each lift needs several passes over damp stone.
- Don't compact the sand bed. Screed it to an even 1 in, then lay pavers on top. Piling extra sand to fix low spots in the base leads to settling, so fix the base instead.
- Slope the base away from buildings by about 1/4 in per foot (roughly 2%) so water drains off rather than soaking the base.
- Include the overhang. Edge restraints need solid base beneath them. Skipping the overhang is a common reason outer rows drift apart.
- Treat polymeric sand as an estimate. Bag coverage varies by brand, so check the label and try our Polymeric Sand Calculator. Apply it only to dry pavers with dry joints and a dry forecast.
Frequently Asked Questions
How deep should my gravel base be for pavers?
A common rule of thumb is 4–6 in of compacted base for a walkway or patio in a mild climate and 6–8 in or more in freeze-thaw regions or on soft, clay-heavy soil. Driveways usually need 8–12 in. Local conditions and codes vary, so check with a local contractor.
Can I use play sand or stone dust under pavers?
No. Use coarse, sharp concrete (bedding) sand for the 1 in layer. Fine play sand and stone dust hold water, compact unevenly and can wash out of joints, which leads to sinking and wobbly pavers.
How many pavers do I need per square foot?
It depends on size and joint width. A 4×8 in brick paver needs 4.5 per sq ft with no joint, or about 4.11 with 1/4 in joints. A 12×12 in paver needs 1.00 per sq ft with no joint, or about 0.96 with 1/4 in joints. This calculator uses your exact dimensions.
How many extra pavers should I order?
Plan on 5–10% for simple rectangles and 15–20% for diagonal, herringbone or curved designs, where more pavers get cut. Buying a few extras also keeps matching stock on hand for later repairs, since colors vary between batches.
Do I need landscape fabric under the base?
Fabric is recommended over soft or clay soils because it keeps the subgrade from mixing into the gravel while still letting water through. It adds a modest cost, and it doesn't change the gravel quantity in this calculator.
How accurate is the polymeric sand estimate?
It's a reasonable planning figure based on joint volume, but coverage varies by brand, joint depth and how much gets swept away. For 12×6 in pavers with 1/4 in joints it works out to about 37 sq ft per 50-lb bag, while large pavers with 1/8 in joints can exceed 100 sq ft per bag.