Bark and wood mulch for beds — light volume, bag or bulk
Mulch Calculator
Mulch in cubic yards = area in square feet × depth in feet ÷ 27. A 20 ft × 8 ft bed with a 3-inch layer needs about 1.5 cubic yards including 5% extra. Enter your bed size and depth to see yards, weight and cost.
Cubic yards to order
1.56 yd³
- Exact volume, before extra
- 1.481 yd³
- Estimated weightTypical density; moisture changes it.
- 0.70 US tons
- Cubic feet
- 42.00 ft³
- Cubic meters
- 1.189 m³
- Estimated cost
Worked examples
Front flower bed
A 24 ft × 6 ft bed with 3 inches of mulch and 5% extra.
1.40 yd³ · ≈ 0.63 US tons
Circular tree ring
A 4 ft diameter ring with 2 inches of mulch, no extra.
0.08 yd³ · ≈ 0.03 US tons
Long path edge
Two matching strips 30 ft × 2 ft at 3 inches, 5% extra.
1.17 yd³ · ≈ 0.53 US tons
Good for
- Annual spring top-ups on established flower and shrub beds
- Tree rings where you must keep mulch off the trunk flare
- Deciding bulk delivery vs bag runs through a narrow side yard
- Matching two identical beds so you do not under-order the second one
Common mistakes
- Piling mulch against tree trunks (“mulch volcanoes”) and trapping moisture
- Ordering like soil by the ton — mulch is light; volume is the useful number
- Going thicker than 4 inches and starving shallow roots of air
- Forgetting that dyed mulch and natural bark settle at different rates
How much mulch do I need?
- Measure length and width of the bed in feet (or use diameter for a circle).
- Pick a depth in inches and convert to feet by dividing by 12. Three inches is 0.25 ft.
- Multiply area × depth for cubic feet, then divide by 27 for cubic yards.
- Add a small waste allowance if the ground is uneven.
- Bagged mulch is often sold in 2 cubic foot bags: multiply cubic yards by 27, then divide by bag size.
Most landscape beds use 2–3 inches of mulch. Thicker layers can hold too much moisture against stems.
Mulch coverage by depth
Cubic yards needed to cover 100 square feet. Multiply by your area ÷ 100.
| Depth | Cubic yards per 100 sq ft |
|---|---|
| 1 in | 0.31 |
| 2 in | 0.62 |
| 3 in | 0.93 |
| 4 in | 1.23 |
Approximate weight per cubic yard
Mulch is light; moisture and wood type change the weight a lot.
| Material | US tons per cubic yard (typical range) | Value used here |
|---|---|---|
| Mulch | 0.3 – 0.6 | 0.45 |
Frequently asked questions
How deep should mulch be?
Two to three inches is a common target for flower beds and around trees. Keep mulch a few inches away from trunks and stems so bark can dry.
How many bags equal one cubic yard?
One cubic yard is 27 cubic feet. With 2 cu ft bags you need about 14 bags; with 3 cu ft bags about 9 bags. Check the bag label.
Should I order bulk or bags?
Bulk is usually cheaper for large beds. Bags are easier for small jobs and for carrying mulch through a house or narrow gate.
Does rubber or rock mulch use the same formula?
Volume is the same: area × depth. Weight and coverage per bag differ by product, so use the supplier’s bag volume or tons-per-yard figure.
Sources and updates
Last reviewed .
- NIST – Unit conversion factors – Length definitions used for unit conversion.
- Mulch density – Typical supplier range. Replace with a named source before treating weight as authoritative.
Estimates for planning. Confirm bag sizes, delivery minimums and weight with your supplier.