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Mulch Calculator — Cubic Yards & Bag Count

Enter your bed dimensions and depth to get cubic yards plus bag counts. Works for all mulch types including shredded wood, bark, dyed mulch, rubber, and straw.

Reviewed October 2026 · by The YardMath Estimating Desk · How we calculate

Area & Depth

5% for neat beds; 10% for irregular edges.

Materials Takeoff
Cubic Yards—
Cubic Feet—
2 cu ft bags needed—
3 cu ft bags needed—
Weight (tons)—

How to Calculate Mulch for Garden Beds

Mulch volume uses the same formula as any coverage material: area times depth, divided by 27 to convert cubic feet to cubic yards.

cubic yards = (total sq ft × depth in feet) ÷ 27

Example: Three flower beds totaling 240 sq ft at 3 inches deep: (240 × 0.25) ÷ 27 = 2.22 cubic yards. With 5% overage: 2.33 yd³ — order 2.5 yards.

Recommended Mulch Depth by Application

ApplicationDepthNotes
Annual flower beds2 inchesLighter mulch preserves moisture
Perennial beds3 inchesStandard recommendation (Penn State Extension)
Tree rings3–4 inchesKeep 3–6 in away from trunk
Vegetable gardens2–3 inchesStraw or untreated wood chips
Paths / walkways4 inchesDeeper to suppress weeds under foot traffic
Erosion control slopes3–4 inchesSecure with erosion fabric if steep

Source: Penn State Extension — Mulching Landscape Trees and Shrubs

Mulch Type Comparison

Mulch Typelb/yd³LifespanBest for
Shredded Wood4501–2 yearsMost beds, budget-friendly
Bark Mulch5402–3 yearsDecorative areas, slow decomp
Dyed/Colored5001–2 yearsCurb appeal, color retention
Rubber Mulch67510+ yearsPlaygrounds, permanent areas
Straw/Hay2701 seasonVegetable gardens, seeding
Compost1,000Breaks downSoil amendment, not top-dress

Bags vs. Bulk: When to Switch

A 2 cu ft bag of shredded wood mulch costs $4–$8 at home centers, which works out to $54–$108 per cubic yard. Bulk mulch from a landscape supplier costs $20–$55 per cubic yard delivered. The break-even point is roughly 2–3 cubic yards (about 2–3 typical planting beds). For anything larger, call a mulch supplier.

Mulch volcano warning: Do not pile mulch against tree trunks or plant crowns ("mulch volcanoes"). Keep mulch at least 3 inches away from trunks. Deep mulch against bark causes crown rot and pest damage. A donut shape around the tree — not a volcano — is correct.

Sources

Frequently asked questions

How much area does one cubic yard of mulch cover?+

At 2 inches deep, 1 cubic yard covers 162 sq ft. At 3 inches (recommended for most beds) it covers 108 sq ft. At 4 inches it covers 81 sq ft.

How deep should I put mulch?+

The general recommendation from Penn State Extension is 2–4 inches for wood mulch in landscape beds. Stay under 4 inches — deeper mulch can compact, repel water, and cause crown rot on plants. Keep mulch at least 3 inches away from tree trunks.

How many 2 cu ft bags equal a cubic yard?+

One cubic yard equals 27 cubic feet, so you need 13.5 bags of 2 cu ft, or 9 bags of 3 cu ft. Buy the largest bag size available for less handling — and get bulk delivery for anything over 3 cubic yards.

What is the lightest type of mulch?+

Straw/hay mulch is the lightest at roughly 270 lb per cubic yard. Shredded wood mulch is about 450 lb/yd³. Rubber mulch is heavier at ~675 lb/yd³ but does not decompose.

Should I include a waste factor for mulch?+

Yes. A 5–10% buffer accounts for uneven spreading, irregular bed edges, and material left on paths. The calculator defaults to 5% for mulch since it does not compact like gravel.

Guides for this calculator

Bagged vs. Bulk Mulch: Which Is Cheaper?

Bulk mulch costs 30–60% less than bagged mulch per cubic yard, but you need a minimum of 2–3 yards to make delivery worthwhile. Here is the break-even math.

How Deep Should Mulch Be?

Mulch should be 2–3 inches deep for most landscape beds. More than 4 inches smothers roots and promotes rot. Here's the right depth for every situation.

Types of Mulch: Which One Is Right for Your Yard?

Wood chips, bark nuggets, straw, rubber, and compost mulch each serve different jobs. This guide covers 7 common mulch types with cost, longevity, and best-use data.

What Is a Cubic Yard? (And How to Visualize It)

A cubic yard equals 27 cubic feet (3 ft × 3 ft × 3 ft). It is the standard unit for ordering mulch, gravel, and concrete. Coverage table and conversion formula inside.

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