Build patios, paths, and beds on reliable bases. Choose soil, load, and drainage settings easily. Get thickness, volume, and weights in seconds, confidently now.
| Scenario | Shape & Area | Soil | Load | Drainage | Recommended Base | Notes |
|---|---|---|---|---|---|---|
| Backyard walkway | Rectangle, 120 ft² | Loam | Walkway | Average | ~5 in | Compact in two lifts. |
| Seating patio | Rectangle, 200 ft² | Clay | Patio | Poor | ~10 in | Consider fabric and better drainage. |
| Garden shed pad | Circle, 8 ft diameter | Sandy | Shed pad | Good | ~6 in | Keep surface level, base slightly sloped. |
A stable garden base limits rutting, rocking, and seasonal settlement. This calculator links thickness to load class, soil behavior, and drainage so the base supports surface layers consistently. Walkways commonly fall in the 4–6 inch range on firm ground, while seating patios often target 6–8 inches for better stiffness. Light-vehicle garden drive lanes may require 8–12 inches to resist pumping and deformation. Aim for long-lasting finished surfaces.
Material ordering starts with area, then multiplies by base thickness to obtain volume. The tool converts common shapes into square measure, then calculates cubic measure with an allowance for compaction and trimming. A 10% allowance often fits small jobs, while irregular edges and soft subgrades can justify 15–20%. If you stage deliveries, break totals into batches to reduce on-site stockpiles and moisture absorption.
Subgrade strength and moisture control drive real-world outcomes. Clay retains water and expands, so it benefits from extra depth and improved drainage. Poor drainage raises settlement risk, increasing the recommended thickness. Freeze–thaw environments add margin because trapped water can heave, then soften during thaw cycles. Where runoff concentrates, consider adding a geotextile separator to reduce fines migration and preserve base porosity.
The calculator estimates weight using typical densities for crushed stone, gravel, sand, and decomposed granite. Weight matters for delivery selection, wheelbarrow planning, and base compaction effort. Heavier, well-graded aggregates generally compact more tightly, improving interlock and reducing future movement under repeated loading. For pavers, angular crushed stone often outperforms rounded gravel.
Excavation depth combines base, bedding, and surface layers, plus a small finish tolerance. Compact in lifts rather than one deep layer; thinner lifts compact more evenly. A gentle slope of about 1–2% helps shed water, reducing saturation and extending surface life, especially around patios and paths. Use the slope drop output to set string lines and verify grades before placing bedding material.
For foot traffic, many sites perform well with 4–6 inches on firm ground. Increase thickness if the soil is clay, stays wet, or you expect frequent wheelbarrow use.
Water reduces subgrade strength and can move fines into the base. Extra depth improves load distribution and helps keep the surface stable when the ground is saturated.
Yes. Loose aggregate shrinks when compacted, and trimming creates offcuts. A 10% allowance is common; raise it for soft subgrades, uneven excavation, or complex borders.
Well-graded, angular crushed stone typically compacts tightly and locks together. Rounded gravel can shift under load, so it is better suited for drainage layers than structural bases.
Set a reference line at the high edge, then measure the required drop over the run. Check grades before bedding placement so water flows away from structures and low spots.
No. It provides planning guidance for common garden builds. Frost depth, soils, and load requirements vary by region, so consult local standards or a professional for critical structures.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.