Calculator
Formula used
The calculator first finds bed area, then multiplies by depth to get volume. It applies compaction and waste to better match real spreading.
- Area depends on shape:
Rectangle:
A = L × W, Circle:A = π × (D/2)², Triangle:A = ½ × B × H, Custom:A = given. - Volume (base):
V = A × depth × beds - Final volume:
Vf = V × compaction × (1 + waste/100) - Conversions:
1 yd³ = 27 ft³,1 m³ = 1000 L.
How to use this calculator
- Select your unit system and bed shape.
- Enter dimensions or a known area.
- Set your target chip depth for coverage.
- Open advanced options for waste, compaction, bags, loads, or cost.
- Press Calculate. Use the export buttons to save results.
Example data table
| Bed type | Area | Depth | Final volume | Bags (2 ft³) |
|---|---|---|---|---|
| Rectangle 20 ft × 4 ft | 80 ft² | 3 in | 0.82 yd³ | 12 |
| Circle 10 ft diameter | 78.54 ft² | 2 in | 0.53 yd³ | 8 |
| Custom area 18 m² | 18.00 m² | 7.5 cm | 1.54 m³ | 28 (60 L) |
Planning coverage for garden beds
Wood chips are usually ordered by volume, but projects start with area and depth. Measure beds in feet or meters, then set a target depth. A common refresh layer is 2–4 in (5–10 cm). New paths often need 3–5 in (7–12 cm) to lock chips together. For mixed spaces, split the job into smaller shapes and add them as separate beds.
Choosing a practical depth
Depth changes volume linearly, so small adjustments matter. For example, an 80 ft² bed at 3 in needs about 20 ft³ before allowances. Increase depth when chips are coarse, when sunlight dries beds quickly, or when you want longer intervals between top-ups. Reduce depth around plant crowns to avoid moisture issues.
Compaction and waste factors
Fresh chips settle after watering and foot traffic. A compaction factor of 1.05–1.20 is typical, with higher values for fluffy chips and deep installs. Waste covers raking losses and uneven edges. Many gardeners start at 5% and raise it to 8–12% for curved borders, slopes, or tight corners. If you spread on windy days, waste can rise noticeably, especially with fine chips.
Comparing bags with bulk delivery
The calculator reports cubic feet, cubic yards, and cubic meters so you can compare suppliers. Remember: 1 yd³ equals 27 ft³. Bagged chips often list volume in ft³ or liters. Converting everything to the same unit helps you decide whether bags, bulk pickup, or delivery is the best value for your bed size. Bulk orders reduce packaging waste and lower cost per volume.
Cost and handling checks
Use the cost section to estimate total spend per yd³, per m³, or per bag. Add a realistic load capacity for your vehicle to estimate trips. The density option provides a weight estimate; many wood chips fall roughly between 250–600 kg/m³ depending on moisture. Weight helps confirm safe hauling and easier wheelbarrow planning. If your supplier sells by “scoop,” ask the approximate yardage per scoop and enter it as load capacity.
FAQs
1) What depth is best for weed control?
Most beds benefit from 2–4 inches, refreshed yearly. For paths, 3–5 inches usually performs better. Avoid piling chips against stems and tree trunks.
2) Why does the calculator include compaction?
Chips settle after rain, watering, and walking. Compaction adds a buffer so your final depth remains close to the target once the layer tightens.
3) Should I use waste even for simple rectangles?
Yes, a small waste factor helps cover spillage and raking losses. For straight beds, 3–6% is often enough, while curves and slopes may need more.
4) How many bags equal one cubic yard?
One cubic yard is 27 cubic feet. Divide 27 by your bag size in ft³ to estimate bags per yard, then multiply by the calculator’s required yards.
5) Can I use this for mulch other than wood chips?
Yes, the volume math is the same for bark, straw, or compost. Update density if you want a better weight estimate for your specific material.
6) Why do I see cubic meters in imperial mode?
Suppliers often quote metric volumes, even when you measure in feet. Showing all major units makes it easier to compare prices and delivery options.