Inputs
Example data table
| Example | Shape | Dimensions | Base (in) | Sand (in) | Waste | Compaction | Base (yd³) | Sand (yd³) |
|---|---|---|---|---|---|---|---|---|
| A | Rectangle | 12 ft × 10 ft | 6 | 1 | 7% | 1.10 | 2.10 | 0.35 |
| B | Rectangle | 16 ft × 12 ft | 8 | 1 | 10% | 1.12 | 4.98 | 0.62 |
| C | Circle | Diameter 14 ft | 5 | 1 | 6% | 1.08 | 2.45 | 0.49 |
Formula used
- Rectangle area: A = L × W
- Circle area: A = π × (D/2)²
- Layer volume: V = A × T
- Adjusted volume: Vadj = V × Compaction × (1 + Waste%)
- Cubic yards: yd³ = ft³ ÷ 27
- Weight: lb = ft³ × Density; tons = lb ÷ 2000
- Cost: Layer cost = tons × unit price; Total adds delivery
Thickness T is converted to feet (in ÷ 12) internally. Metric inputs are converted to feet and inches before calculation.
How to use this calculator
- Select a unit system and your patio shape.
- Enter dimensions: length/width for rectangle or diameter for circle.
- Set base and sand thickness to match your design.
- Adjust compaction and waste for real-world purchasing.
- Optionally enter densities and unit prices for cost estimates.
- Click Calculate, then export results as CSV or PDF.
Professional guide to planning a patio base
1) Base purpose and performance
A patio base distributes loads, reduces settlement, and improves drainage beneath pavers or slabs. A well-graded, compacted layer helps prevent rocking pavers, joint washout, and low spots that collect water after rain.
2) Sizing the excavation
Excavation depth typically equals base thickness plus bedding sand, plus the finished surface layer. For example, a 6 in base and 1 in sand bed require roughly 7 in below the top of the pavers, then add any geotextile or leveling tolerance. Confirm clearance at thresholds and drains before digging.
3) Base layer thickness targets
Light pedestrian patios often use 4–6 in of compactable aggregate. Heavier loads, poor soils, or freeze–thaw exposure may need 6–10 in. Your design should follow local practice and site conditions, especially where drainage is slow. Place the base in compacted lifts (often 2–3 in) for better density.
4) Bedding sand role
Bedding sand is a thin leveling layer, not a structural layer. A common target is about 1 in after screeding. Too thick a sand layer can rut under load and can make compaction less effective. Keep the sand clean and consistent to maintain even support.
5) Compaction and waste factors
Bulk material placed loose will compact to a smaller final volume. The calculator applies a compaction factor and an extra waste percentage for spillage, grading, and edge trimming. Typical combined purchasing allowances range from 10–20% depending on crew, access, and layout complexity. Use a higher waste value for hand grading or long carry distances.
6) Converting volume to tons
Suppliers often sell by weight. The calculator multiplies computed cubic feet by density (lb/ft³) to estimate tons. Because density depends on moisture, grading, and quarry source, confirm the supplier’s “tons per yard” conversion for the exact product you will receive.
7) Drainage, slope, and edge restraint
A stable base still needs water management. A gentle slope away from structures (commonly around 2%) and proper edge restraint reduce lateral movement. Combine this with compacted lifts and clean jointing practices to extend service life.
8) Using results for ordering
Use the cubic yards to plan truckload quantities and the tonnage to compare supplier quotes. Include delivery fees to avoid budget surprises. Export the CSV or PDF to share requirements with your supplier or crew, and re-check quantities if you revise thickness or shape. Keep unit conversions with your project notes for repeatable ordering.
FAQs
1) What base material should I choose?
Use a compactable, well-graded aggregate commonly sold as road base, crusher run, or similar. The best option depends on local availability, drainage needs, and the surface you’re installing.
2) Why does compaction increase the purchase amount?
Loose material contains more air voids than a compacted layer. A compaction factor adds extra volume so that, after densifying in lifts, you still achieve the target finished thickness.
3) How accurate are density-based ton estimates?
They are planning estimates. Moisture content, grading, and quarry source change density. For purchasing, confirm the supplier’s conversion (tons per cubic yard) for the exact product you will receive.
4) Should I include the paver thickness in the calculation?
This tool sizes base and bedding layers only. Add paver or slab thickness separately to determine total excavation depth and finished elevation relative to doors, drains, and adjacent surfaces.
5) What waste percentage is reasonable?
Many projects use 5–10% for waste, higher for tight access, multiple grades, or heavy shaping. Use a conservative value if you expect rework, steep slopes, or long hauling distances.
6) Can I use metric inputs?
Yes. Choose metric to enter meters and centimeters. The calculator converts units internally and shows the same core outputs, with additional metric area, volume, and weight equivalents for convenience.
7) Why are my results different from a supplier quote?
Suppliers may quote by a standard “yards-to-tons” factor for their product, or include minimum loads and delivery rules. Align your density and pricing with the supplier’s published conversion for the closest match.