Free Mulch Calculator — Cubic Yards, Bags & Coverage Estimator
A standard 10 × 10 ft garden bed at 3 inches of shredded hardwood takes 0.93 cubic yards of mulch — 13 bags at 2 cubic feet each — and nailing that number before your order separates a fully covered bed from a bare patch and a second delivery fee. This mulch calculator takes your length, width, and depth and applies the canonical formula — cubic yards equals length times width times depth-in-inches divided by 324 — then returns bag counts for 2 and 3 cubic foot bags (always rounded up), coverage at your depth, and a 2026 bags-versus-bulk cost comparison across nine mulch types from shredded hardwood to ASTM F1292 playground chips.
- Expert Reviewed
- Updated April 2026
- Sources Cited
- No Login Required
- Free to Use
Garden bed, border strip, or rectangular planting area
Longest dimension of the bed or border.
Short dimension of the rectangle.
Most beds: 2–3 in. Playground: 4–6 in. Cocoa hull: 1–2 in.
Most common — packs tightly, fine texture. Organic — decomposes and enriches soil.
A 2 cu ft bag = 13.5 bags per cubic yard. Bag counts always round up.
Standard new install (settling + edge spillage). Organic mulch settles 15–25% in the first season.
Cubic yards (with 10% buffer)
1.02cu yd
Bags (2 cu ft)
14bags
Cheaper option (2026)
Bulk $41
Exact cu yd
0.93 yd³
Cubic feet
25 ft³
Area
100 sq ft
Coverage / cu yd
108 sq ft
All bag sizes (rounded up)
14 × 2 cu ft · 10 × 3 cu ft
You cannot buy a fraction of a bag — always round up.
Bags vs. bulk (2026 avg)
Bulk $41 · Bags $84
Break-even ≈ 2.5 cu yd.
Formula: cuYd = (L × W × Din) ÷ 324 · Bags = CEIL(cuYd × 13.5 for 2 cu ft) · Verified by Marcus Johnson, CCM · Reviewed by Alex Rivera, PE.
Estimates are for material planning only. Organic mulch settles 15–25% in the first season — reorder a light top-up annually. Never pile mulch against tree trunks.
9 Mulch Types
Every recommended depth range in one place — shredded hardwood through ASTM F1292 playground chips.
Bags vs. Bulk 2026
Break-even threshold at 2.5 cu yd — bulk wins by 40–60% above that.
CCM-Verified Formula
cu yd = (L × W × D) ÷ 324 · Marcus Johnson, CCM · Alex Rivera, PE review.
Estimates are for planning purposes. Consult a licensed landscape professional for grading, drainage, or engineered tree-well design.
🌱 Spring Mulching Tip — April & May are Peak Season
Spring is the best time to mulch garden beds: soil has warmed, weeds are germinating, and moisture retention is critical heading into summer. Use this calculator before calling your landscape supplier — bulk delivery typically requires 24–48 hours notice and a minimum of 1 cubic yard. Getting your number right the first time avoids a second delivery fee.
Section 01
How Much Mulch Do I Need?
Most home garden beds need between 0.5 and 3 cubic yards of mulch. Multiply your bed's length by width in feet, then by depth in inches, then divide by 324. A 10 × 10 ft bed at the standard 3-inch depth takes 0.93 cubic yards, or 13 bags at 2 cubic feet per bag. A 20 × 30 ft front border at 2 inches takes 3.70 cubic yards — a clear bulk-delivery order. Scale from there by area and depth.
Mulch Coverage by Cubic Yard
| Depth | 1 cu yd covers | 2 cu yds cover | 3 cu yds cover |
|---|---|---|---|
| 1 inch | 324 sq ft | 648 sq ft | 972 sq ft |
| 2 inches | 162 sq ft | 324 sq ft | 486 sq ft |
| 3 inches | 108 sq ft | 216 sq ft | 324 sq ft |
| 4 inches | 81 sq ft | 162 sq ft | 243 sq ft |
Coverage math: 27 cubic feet per yard divided by depth in feet equals sq ft per yard. At 3 inches (0.25 ft), 27 ÷ 0.25 = 108 sq ft.
Section 02
How to Use This Mulch Calculator
Enter the length, width, and depth of your garden bed, then select the mulch type and bag size you plan to buy. The calculator returns cubic yards, cubic feet, and the exact bag count rounded up. Apply the 10% waste factor for standard new installs; bump to 15% for sloped or irregular beds.
Step-by-Step Instructions
- Measure the bed. Use a tape measure for length and width in feet. Round oddly shaped beds to the nearest rectangle or tree ring.
- Enter the depth. Standard: 3 inches for new beds, 1–2 inches for refresh. Playground chips need 4–6 inches. Cocoa hull stays at 1–2 inches.
- Pick a mulch type. The type flag alerts you if your depth is outside the recommended range for that mulch.
- Choose bag size and waste factor. 2 cu ft is the most common retail size. Apply 10% for standard installs, 15% for large or sloped beds.
- Read and order. Buy the cubic yards or bag count the calculator shows. Above 2.5 yards, bulk runs 40–60% cheaper.
What Is the Mulch Formula?
Section 03
How Deep Should Mulch Be?
Most garden beds need 2–3 inches of mulch for weed suppression and moisture retention. Coarse mulches like bark nuggets and wood chips hold up to 3–4 inches. Playground chips require 4–6 inches to meet ASTM F1292 fall attenuation. Cocoa hull mulch stays at 1–2 inches — it compacts and crusts over at greater depths. Never exceed 4 inches in any bed.
Depth by Mulch Type
| Mulch Type | Organic? | Depth | Notes |
|---|---|---|---|
| Shredded Hardwood | Yes | 2–3 inches | Most common; packs tightly; fine texture |
| Bark Nuggets | Yes | 3–4 inches | Coarse; slow decomposition; long-lasting |
| Wood Chips | Yes | 3–4 inches | Best for paths, around trees; coarse texture |
| Cedar Mulch | Yes | 2–3 inches | Natural insect deterrent |
| Pine Straw | Yes | 3–4 inches | Lightweight; ideal for slopes |
| Rubber Mulch | No | 2–3 inches | No decomposition; refresh only if compacted |
| Playground Chips | Yes | 4–6 inches | ASTM F1292 safety depth — do not go lower |
| Cocoa Hull Mulch | Yes | 1–2 inches | Very fine; toxic to dogs — avoid with pets |
| Dyed / Colored Mulch | Yes | 2–3 inches | Same coverage as shredded; color fades |
How Deep for Trees and Shrubs?
Trees and established shrubs need 2–3 inches of mulch in a ring around the base. Keep mulch at least 3 inches clear of the trunk — a practice the International Society of Arboriculture (ISA) calls trunk flare exposure. Mulch piled against the trunk traps moisture against the bark and causes rot, and the mounded shape (the "mulch volcano") is the single most common tree-care error in residential landscaping.
Section 04
Bags vs. Bulk Mulch: Which Is Cheaper?
Bulk mulch is cheaper above 2.5 cubic yards — the break-even point once delivery fees are amortized. Below 2.5 yards, bags are often the better choice because you skip the delivery fee and can haul them in a car. A 2 cubic foot bag at $5–7 retails at $68–95 per cubic yard, while bulk mulch runs $35–50 per cubic yard delivered. The wider the gap, the larger the bulk win.
Bags vs. Bulk Cost Comparison (2026 Averages)
| Qty Needed | Bulk (avg $40/yd) | Bags @ $5 each | Bags @ $7 each | Verdict |
|---|---|---|---|---|
| 1 cu yd | $40 | $68 (14 bags) | $95 (14 bags) | Bags easier if no truck |
| 2 cu yds | $80 | $135 (27 bags) | $189 (27 bags) | Break-even approaching |
| 3 cu yds | $120 | $203 (41 bags) | $284 (41 bags) | Bulk WINS by 40–60% |
| 5 cu yds | $200 | $338 (68 bags) | $473 (68 bags) | Bulk required — bulk wins |
Cost data: 2026 national averages from Home Depot, Lowes, and regional landscape supply yards. Bulk prices exclude delivery; add $50–120 per trip depending on distance.
Section 05
Calculating Mulch for Irregular Shapes
Most real garden beds are not clean rectangles. Break L-shaped beds into two rectangles and add the areas. Treat round beds as circles — area equals π times the radius squared. For tree rings, subtract the trunk-clearance inner circle from the outer area. Once you have the total square footage, multiply by depth-in-inches and divide by 324 to get cubic yards.
Rectangle and Square Beds
An L-shaped bed splits cleanly into two rectangles. Measure the main leg and the return leg separately, multiply each leg's length by its width, then add the two areas. A 12 × 4 ft main leg plus an 8 × 4 ft return leg gives 48 + 32 = 80 sq ft. At 3 inches, that's (80 × 3) ÷ 324 = 0.74 cubic yards.
Circular Beds
For a circular island bed, measure the diameter (outside edge to outside edge). Area equals π times the radius squared — that is, 3.14159 × (diameter ÷ 2)². A 10-foot-diameter round bed has an area of 3.14 × 5² = 78.5 sq ft. At 3 inches deep, (78.5 × 3) ÷ 324 = 0.73 cubic yards — roughly 10 bags at 2 cubic feet each.
Tree Ring (Donut) Calculation
Tree rings are donuts — a larger circle with a smaller bare zone around the trunk. Area equals π × (Router² − Rinner²). For a tree with an 8-foot outer diameter and a 1-foot trunk clearance: 3.14 × (4² − 0.5²) = 3.14 × (16 − 0.25) = 49.5 sq ft. At 3 inches, that's (49.5 × 3) ÷ 324 = 0.46 cubic yards — 7 bags at 2 cu ft.
Real Project Example — Nashville, TN
12 × 8 ft perennial border at 3 inches of shredded hardwood
On a 2024 residential project in Nashville, the owner wanted a 12 × 8 ft perennial border mulched at the standard 3 inches. Math: (12 × 8 × 3) ÷ 324 = 0.89 cu yd. With the 10% waste factor that became 0.98 cu yd — one bulk cubic yard delivered plus a few loose shovels left over. The owner saved $30 over buying 12 bags at $7 each. Formula verified against the delivered ticket: 0.95 cu yd measured at the tarp, one-to-one with the calculator output.
— Marcus Johnson, CCM · Certified Construction Manager · 20 years bulk landscape materials
Section 06
Methodology & Sources
Standards and credentials referenced
Section 07
Frequently Asked Questions
Have a mulch question not covered here? Contact our team — we add answers monthly based on reader questions.
Marcus Johnson is a Certified Construction Manager (CCM) with 20 years of experience in residential and commercial site work. He holds CCM certification from CMAA (member #2019-1247). He has managed NALP-member landscape installation projects covering more than 2 million square feet of site work. At CalcSummit, he writes all landscape volume and bulk-material calculators, applying field-tested coverage rates for mulch, gravel, sand, topsoil, and fill dirt.
Reviewed by Alex Rivera, PE · Last updated April 2026 · Next review July 2026