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Mulch Calculator: How Much Mulch Do I Need in Yards and Bags

Last updated Researched from specs, manuals and owner reviews, not tested in person

Quick answer

Multiply bed area in square feet by depth in inches, then divide by 324 to get cubic yards. One cubic yard covers 108 square feet at 3 inches deep and equals 13.5 bags of 2 cubic feet or 9 bags of 3 cubic feet. A 200 square foot bed at 3 inches needs about 1.85 yards, or 25 small bags.

Mulch is sold two ways, by the cubic yard in bulk and by the bag in cubic feet, and the math between them trips people up. Enter each bed's size and the depth you want, choose a bag size, and the calculator returns cubic yards, bags, approximate weight and how many wheelbarrow or cart loads it takes to move. Buying gravel or topsoil instead? Use the gravel calculator or the topsoil calculator.

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1.85 cubic yards

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On this page
  1. How much mulch do I need for my bed size?
  2. How many bags of mulch are in a yard?
  3. How is mulch calculated?
  4. How deep should mulch be?
  5. Is bulk mulch cheaper than bags?
  6. Should I put landscape fabric under mulch?

How much mulch do I need for my bed size?

Cubic yards and 2 cubic foot bags by bed area and depth.

Mulch needed by area and depth
Bed area2 in deep3 in deep4 in deep
50 sq ft0.31 yd / 5 bags0.46 yd / 7 bags0.62 yd / 9 bags
100 sq ft0.62 yd / 9 bags0.93 yd / 13 bags1.23 yd / 17 bags
200 sq ft1.23 yd / 17 bags1.85 yd / 25 bags2.47 yd / 34 bags
300 sq ft1.85 yd / 25 bags2.78 yd / 38 bags3.7 yd / 50 bags
500 sq ft3.09 yd / 42 bags4.63 yd / 63 bags6.17 yd / 84 bags
1000 sq ft6.17 yd / 84 bags9.26 yd / 125 bags12.35 yd / 167 bags

How many bags of mulch are in a yard?

Bag sizes and coverage
UnitBags per cubic yardCovers at 2 inCovers at 3 inCovers at 4 in
2 cu ft bag13.512 sq ft8 sq ft6 sq ft
3 cu ft bag918 sq ft12 sq ft9 sq ft
1.5 cu ft bag189 sq ft6 sq ft4.5 sq ft
1 cubic yard (bulk)1162 sq ft108 sq ft81 sq ft

How is mulch calculated?

Mulch volume is area times depth, converted to cubic yards:

  • Cubic feet = area in square feet x depth in inches / 12
  • Cubic yards = cubic feet / 27, which simplifies to area x depth in inches / 324
  • Bags = cubic feet / bag size in cubic feet, rounded up

For a circle, area is 3.1416 x radius x radius, so a 6 foot ring around a tree (3 foot radius) is 28 square feet, minus the trunk. For a curved bed, measure the length along its center and average several widths. The calculator's weight estimate uses a typical 400 to 800 pounds per cubic yard for dry shredded wood mulch; wet mulch weighs much more, which matters when you are deciding between a wheelbarrow and a cart.

How deep should mulch be?

Recommended mulch depth
SituationDepthWhy
Annual refresh over existing mulch1 inEnough to restore color; deeper layers pile up year over year
Shredded hardwood or bark, new beds2 to 3 inThe standard range for weed suppression and moisture
Pine straw2 to 3 in settled (3 to 4 in fluffed)Settles quickly; spread thicker at first
Wood chips or nuggets3 inLarger pieces need a little more depth to block light
Around trees2 to 3 in, pulled back 3 to 6 in from the trunkNever pile against the trunk (no mulch volcanoes)
Rubber mulch or play areasFollow the product and safety surfacing guidancePlay surfaces need far more depth than beds

Is bulk mulch cheaper than bags?

Usually, once you need more than about 2 to 3 cubic yards. Bulk mulch is priced per yard plus a delivery fee, so small jobs favor bags and large jobs favor a delivered pile. The hidden cost of bulk is moving it: 3 yards is roughly 20 to 30 loads in a standard 6 cubic foot wheelbarrow, or about half that in a 10 to 15 cubic foot cart. A two-wheel wheelbarrow like the Jackson MP1010 10 cu ft Poly 2-Wheel Wheelbarrow or a poly dump cart like the Gorilla Carts Poly Dump Cart, 1,500 lb, 10 cu ft halves the trips and is far more stable for older backs, and a lawn tractor with a tow-behind cart such as the Ohio Steel 4048P-HYB 15 cu ft Poly Swivel Hybrid Dump Cart makes a big delivery a short job. A 10 tine fork like the Truper TruTough 10-Tine Ensilage Fork loads mulch faster than a shovel. Carts are compared in wheelbarrow vs yard cart.

Should I put landscape fabric under mulch?

Under stone and gravel, yes: fabric keeps rock from sinking into the soil. Under wood mulch, it is optional and often counterproductive, because the mulch breaks down into a thin soil layer on top of the fabric where weeds root anyway, and fabric makes adding plants later harder. Where you do want it, under paths or rock beds, a woven commercial-grade barrier such as the DeWitt Pro-5 Weed Barrier Fabric (6 x 250 ft.) lasts far longer than thin spun fabric. Clean bed edges do more to keep mulch in place than fabric: no-dig edging like EasyFlex Heavy Duty No-Dig Edging Kit (100 ft.) is an afternoon job. See how to mulch landscape beds.

Frequently asked questions

How many bags of mulch do I need for 100 square feet?

At 3 inches deep, 100 square feet needs 25 cubic feet of mulch, which is about 0.93 cubic yards. That is 13 bags of 2 cubic feet or 9 bags of 3 cubic feet. At 2 inches deep, the same bed needs 9 small bags. Add a bag or two for uneven ground and edges.

How much does a yard of mulch cover?

One cubic yard of mulch covers 324 square feet at 1 inch deep, 162 square feet at 2 inches, 108 square feet at 3 inches and 81 square feet at 4 inches. For most beds, plan on 3 inches for new mulch and 1 inch for a yearly top-up, so a yard covers about 108 square feet of new bed or about 324 square feet of refresh.

How many bags of mulch make a yard?

A cubic yard is 27 cubic feet, so it takes 13.5 bags of 2 cubic feet, 9 bags of 3 cubic feet or 18 bags of 1.5 cubic feet to equal one yard of bulk mulch. When comparing prices, divide the bulk price per yard by the bag count to get an equivalent price per bag, then add any delivery fee.

Should I remove old mulch before adding new mulch?

Usually not. Old mulch that has broken down is improving the soil. Rake it to loosen any matted crust, pull back anything piled against trunks or siding, and add about 1 inch of fresh mulch to restore color. Remove old mulch only if the total depth is already over 3 to 4 inches, it is moldy and compacted, or you are changing to stone.

How much does a cubic yard of mulch weigh?

Dry shredded hardwood or bark mulch typically weighs roughly 400 to 800 pounds per cubic yard, and wet mulch can weigh considerably more. Rubber mulch is heavier. That matters for pickup trucks, which often carry 1 to 2 yards safely, and for how much you load into a wheelbarrow at once. A 2 cubic foot bag of dry mulch usually weighs about 20 to 30 pounds.

Researched, not professional advice. This page is compiled from published specifications, manuals, labels and owner-review consensus, not hands-on testing. Follow the manufacturer's instructions and product label, and consult a qualified professional where safety, chemicals, fuel or structures are involved. As an Amazon Associate we earn from qualifying purchases.