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CalcBelt

Mulch calculator

Enter your beds or tree rings and the depth to see how many cubic yards or bags of mulch to buy, and what bulk or bagged mulch will cost.

Units
Shape

2 to 3 in for most beds, up to 4 in around trees and shrubs.

Identical beds or tree rings.

%

Optional, for uneven ground or topping up.

Keep mulch a few inches away from stems and at least 6 in from tree trunks. Never pile it into a cone around a tree.

Mulch needed

0.93 cubic yards

25 cubic feet · covers 100 sq ft

3 cu ft bags
9
2 cu ft bags
13
1.5 cu ft bags
17

Cost estimate

per cubic yard

Bulk: $46.30 plus delivery

Typical US price $25 to $100 per cubic yard (HomeGuide, HomeAdvisor, LawnStarter, October 2026). Delivery usually adds $50 to $150.

per 2 cu ft bag

Bags: $52 for 13 bags of 2 cu ft

Typical US price $3 to $6.50 per 2 cu ft bag (Home Depot, LawnStarter, October 2026).

How it's calculated
  1. Area: 100 sq ft × depth 3 in = 25 cu ft
  2. 25 cu ft ÷ 27 = 0.93 cubic yards
  3. Bags: 25 cu ft ÷ 2 cu ft = 12.5, rounded up to 13 bags

Estimates use manufacturer data sheets and industry guides (sources). Check local codes and your supplier's figures before you order.

How to use the mulch calculator

  1. Pick the shape of the bed: rectangle, circle, triangle, a ring around a tree, or Known area to type the square footage.
  2. Enter its size. For several beds of the same size, set How many.
  3. Enter the depth: 2 to 3 in for most beds, up to 4 in around trees and shrubs.
  4. Read the cubic yards for bulk mulch, or the number of 1.5, 2 or 3 cubic foot bags.

How to calculate mulch

Cubic yards = area (sq ft) × depth (in) ÷ 324

That shortcut works because a cubic yard spread 1 inch deep covers 324 square feet (27 cubic feet × 12).

Example: two flower beds of 20 × 4 ft, mulched 3 in deep, are 160 sq ft. 160 × 3 ÷ 324 = 1.48 cubic yards, which is 40 cubic feet: 20 bags of 2 cubic feet, or 14 bags of 3 cubic feet.

Tree ring example: a ring 8 ft across with a 2 ft bare circle around the trunk is about 47.1 sq ft. At 3 in deep that’s 11.8 cubic feet, or 6 bags of 2 cubic feet.

How deep to mulch

Where Depth
Annual and perennial flower beds 1 to 2 in
Shrub and mixed beds 2 to 3 in
Around trees and shrubs on well-drained soil 3 to 4 in
Around trees on heavy clay 2 to 3 in

Topping up an existing bed? Measure how much is left and only add the difference, so the layer doesn’t get deeper every year. Old mulch breaks down and settles over time.

Bags or bulk

Bagged mulch is easy to carry and store, and comes in 1.5, 2 and 3 cubic foot bags. Bulk mulch is sold by the cubic yard and is usually cheaper per yard, but most suppliers charge for delivery. Compare the bulk price plus delivery with the cost of 14 bags of 2 cubic feet per yard.

To fill a new bed before mulching it, the topsoil calculator works out the soil, and the gravel calculator handles stone by the ton.

Questions and answers

How much mulch do I need?

One cubic yard for every 108 sq ft of bed at 3 in deep, or one 2 cu ft bag for every 8 sq ft. In general, multiply length × width in feet by the depth in inches and divide by 12 for cubic feet, then by 27 for cubic yards. A 12 × 15 ft bed at 3 in needs 45 cu ft: 1.67 cubic yards or 23 bags of 2 cu ft.

How deep should mulch be?

2 to 3 inches for most beds, according to extension services such as Clemson and the University of Florida. Around trees and shrubs, 2 to 4 inches (University of Nebraska), and 1 to 2 inches around annual and perennial flowers.

How many bags of mulch are in a yard?

13.5 bags of 2 cubic feet (buy 14), 9 bags of 3 cubic feet, or 18 bags of 1.5 cubic feet. A cubic yard is 27 cubic feet.

How much does a yard of mulch cover?

324 square feet at 1 inch deep, 162 at 2 inches, 108 at 3 inches and 81 at 4 inches.

How much does a 2 cubic foot bag of mulch cover?

12 square feet at 2 inches deep, or 8 square feet at 3 inches. A 3 cubic foot bag covers 12 square feet at 3 inches.

Should mulch touch the tree trunk?

No. Keep mulch at least 6 inches from tree trunks (Iowa State) and a hand's width from plant stems (Clemson). The University of Nebraska says never to apply mulch against the bark of trees or shrubs, and extension services warn against piling it into a cone, sometimes called a mulch volcano.

How much is a yard of mulch?

Bulk mulch usually costs $25 to $100 per cubic yard before delivery, which adds about $50 to $150 (HomeGuide, HomeAdvisor, LawnStarter). Bagged mulch runs about $3 to $6.50 per 2 cubic foot bag.

How much will 25 bags of mulch cover?

25 bags of 2 cu ft hold 50 cu ft: enough for 200 sq ft at 3 in deep or 300 sq ft at 2 in.

Is it cheaper to buy mulch in bulk or in bags?

Per yard they are close: a cubic yard is 13.5 bags of 2 cu ft, about $44 to $88 at LawnStarter's $3.25 to $6.50 a bag, while HomeGuide puts bulk mulch at $25 to $100 a yard plus $50 to $150 for delivery. Bulk pays off on bigger jobs, where the delivery fee is spread over more yards.

Sources

Figures checked October 2026.