| Bed | Shape | Dimensions | Thickness | Allowances | Approx. volume |
|---|---|---|---|---|---|
| Front border | Rectangle | 20 ft × 10 ft | 3 in | 7.5% waste, 10% settling | ~0.76 yd³ |
| Tree ring | Circle | 12 ft diameter | 4 in | 5% waste, 10% settling | ~1.55 yd³ |
| Corner bed | Triangle | Base 16 ft, height 8 ft | 2.5 in | 10% waste, 10% settling | ~0.54 yd³ |
- Rectangle area:
A = L × W - Circle area:
A = π × (D/2)² - Triangle area:
A = 0.5 × B × H - Base volume:
V₀ = A × t - Final volume:
V = V₀ × (1 + waste%) × (1 + settling%) - Cubic yards:
yd³ = ft³ / 27 - Weight (optional):
Weight = density × volume - Bags:
bags = ceil(ft³ / bag_size)
- Select your unit system and bed shape.
- Enter dimensions, or enter the area if already measured.
- Set mulch thickness based on your planting needs.
- Add waste and settling allowances for realism.
- Optionally add density to estimate weight for hauling.
- Enter bag size and prices to compare bagged vs bulk.
- Press Calculate, then download CSV or PDF if needed.
1) Measure the bed the same way you will spread
Accurate mulch ordering starts with consistent measuring. For rectangles, measure the longest length and widest width at the soil line. For circles, measure the full diameter, not the radius. If a bed is irregular, split it into smaller rectangles or triangles, calculate each area, then add the areas together before applying thickness.
2) Choose a practical thickness for wood chips
Wood chips are commonly applied at 2–4 inches (about 5–10 cm). Thinner layers may expose soil after settling, while overly thick layers can reduce air exchange around stems. This calculator converts thickness to feet or meters internally, then multiplies by area to estimate a base volume before allowances.
3) Add waste and settling factors for real-world results
Field conditions rarely match perfect geometry. Waste covers spillage, edging, and uneven surfaces; 5–10% is a typical planning range. Settling accounts for compaction after watering and rainfall; 8–15% is common for loose chips. The final volume is computed as V = A × t × (1+waste) × (1+settling).
4) Compare bagged mulch versus bulk deliveries
Bagged mulch is convenient for small projects and tight access. Common bag sizes are 1.5–3.0 ft³, and the calculator rounds bag counts up using ceil(). Bulk mulch is usually quoted per cubic yard or cubic meter; this tool reports both so you can compare suppliers with different units.
5) Plan handling with weight and truck-load estimates
If you enter a bulk density, the calculator estimates weight to help with trailer limits and labor planning. Loose wood chips often fall in the 240–480 kg/m³ range, depending on moisture and chip size. Truck loads are estimated by dividing total volume by your selected capacity and rounding up to avoid under-ordering.
1) What thickness should I use for most garden beds?
For most beds, 2–4 inches (5–10 cm) is a practical range. Use thinner layers near seedlings and thicker layers on paths or around established shrubs, keeping chips away from stems.
2) Why does the calculator include settling allowance?
Wood chips compress after watering and over time. Settling allowance helps you order enough material so the finished depth remains close to your target instead of dropping noticeably.
3) How do I estimate an irregular-shaped bed?
Break the bed into simple shapes you can measure, like rectangles and triangles. Add the areas together, then use the “I already know the area” option to calculate volume from the combined area.
4) Are cubic yards and cubic meters both shown?
Yes. The results display volume in cubic yards, cubic meters, and cubic feet. This helps you compare quotes from suppliers who price material in different unit systems.
5) What density should I enter for weight estimation?
If you do not have supplier data, start with about 320 kg/m³ (or roughly 20 lb/ft³) for loose chips. Wet chips can be heavier, so increase the value if moisture is high.
6) Why are bag counts rounded up?
You cannot purchase a fraction of a bag. The calculator uses rounding up so you do not run short, especially when you also account for waste and settling in the final volume.
7) Should I order extra beyond the allowances?
For multi-bed projects or hard-to-match colors, ordering a small additional margin can be useful. If storage is limited, rely on the waste and settling settings and confirm availability with your supplier.