Quantity · Mulch
Mulch Calculator
Size bulk or bagged mulch from bed length, width, and depth. One cubic yard covers about 108 square feet at 3 inches — the standard US landscaping rule. Toggle the primary result between yards and 2 cu ft bags. Keep mulch off trunks.
Bed size
Typical decorative beds — do not pile against trunks.
Keep mulch a few inches away from trunks and stems — never volcano-mound against bark.
Cubic yards to order
1.56cu yd
~21 bags (2 cu ft each)
- Area
- 160 sq ft
- Depth
- 3"
- Coverage / cy
- ~108 sq ft
- With waste
- 1.56 cy
- Bulk yards
- 1.56
- 2 cu ft bags
- ~21
Rule of thumb: 1 cubic yard covers about 108 sq ft at 3". Bags are 2 cu ft (13.5 per yard). Bulk wins once you need more than a few bags.
- Area = length × width
- Yards = area ÷ (108 × 3 ÷ depth)
- Bags = yards × 13.5 (2 cu ft bags)
Price data updated . National US ranges from published supplier and contractor averages. Not a bid. Local quotes vary.
How mulch quantity is calculated
Coverage scales with depth: shallower mulch spreads farther per yard. Cubic yards equal area divided by coverage at your depth. Bags assume 2 cubic feet each (13.5 bags per yard).
area_sq_ft = length × width coverage/cy = 108 × (3 / depth_in) // 108 sq ft at 3" cubic_yards = area / coverage_per_cy yards_order = cubic_yards × (1 + waste %) bags = ceil(yards_order × 13.5) // 2 cu ft bags
Worked example. A 20 × 8 ft bed (160 sq ft) at 3": coverage 108 sq ft/cy → 1.48 cy raw. With 5% waste → 1.56 cy → about 21 bags of 2 cu ft. At 2" the same bed needs only ~1.04 cy.
Mulch coverage by depth
Anchored to 1 cubic yard = 108 sq ft at 3" (US landscaping standard). Other depths scale inversely. This chart is the unique reference for the mulch page.
| Depth | Sq ft per cy | 2 cu ft bags / 100 sq ft | Typical use |
|---|---|---|---|
| 1" | 324 | ~5 | Light refresh over existing mulch |
| 2" | 162 | ~9 | Flower and shrub beds |
| 3" | 108 | ~13 | Standard beds / weed control start |
| 4" | 81 | ~17 | Heavier weed suppression |
- 13.5 bags of 2 cu ft = 1 cubic yard.
- Never mound mulch against tree trunks — leave a few inches of clear bark.
Depth guidance
Presets in the calculator. Adjust for your soil and plantings.
| Goal | Depth | Notes |
|---|---|---|
| Decorative beds | 2–3" | Most common residential depth |
| Weed suppression | 3–4" | Thicker layer blocks more light |
| Refresh existing mulch | 1–2" | When soil is already covered |
| Around trunks | keep clear | No volcano mounds against bark |
Mulch calculator FAQ
- How much mulch do I need?
- At 3 inches, plan about 1 cubic yard per 108 square feet of bed. Shallower depths cover more area per yard; deeper covers less. This calculator converts your bed size to yards and 2 cu ft bags.
- How many bags of mulch equal a cubic yard?
- About 13.5 bags if each bag is 2 cubic feet (the most common retail size).
- How deep should mulch be?
- Usually 2–3 inches for beds and 3–4 inches when you want stronger weed suppression. Do not pile mulch against tree trunks.
- Should I buy bags or bulk?
- Bags are handy for small beds. Once you need more than a few bags, bulk cubic yards are almost always cheaper.
- Does mulch type change the volume?
- Hardwood, dyed, and cedar mulches use the same coverage math by volume. Weight and price differ — order by the cubic yard or bag count, not by pounds.
- Is this related to the gravel calculator?
- Different material. Use gravel tools for stone and sand; this page is for organic mulch beds only.
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