Measure your bed, choose a depth (2 to 3 inches is right for most gardens) and the calculator below shows how many cubic yards or bags of mulch you need. Add the prices from your garden center and it compares bagged and bulk costs side by side. Quick rule: one cubic yard covers about 108 square feet at 3 inches deep, the same as 13.5 bags of 2 cubic feet.
Mulch Calculator
Results update as you type. Use decimals for partial feet (8 ft 6 in = 8.5).
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1 cubic yard = 27 cubic feet = 13.5 bags of 2 cu ft. It covers about 108 sq ft at 3 inches deep. Bag counts are rounded up; bulk prices usually exclude delivery.
How deep should mulch be?
Depth matters more than most people think. Too thin and weeds push through; too thick and water and air struggle to reach the roots. Clemson University’s Home & Garden Information Center recommends a 2- to 3-inch layer for common mulches like pine bark, pine needles and wood chips.
| Where | Depth | Why |
|---|---|---|
| Flower and shrub beds | 2–3 in | Enough to block weeds and hold moisture |
| Around trees | 2–3 in, kept a few inches off the trunk | Mulch piled against bark traps moisture and invites rot |
| Vegetable gardens | 2–3 in (straw, leaves) | Easy to work into the soil at season’s end |
| Garden paths | 3–4 in | Foot traffic packs it down |
| Home play areas (wood chips) | 9 in or more | The CPSC’s playground safety guidance for fall protection |
For play areas, the U.S. Consumer Product Safety Commission’s Public Playground Safety Handbook (PDF) calls for a 9-inch layer of loose-fill like wood chips or mulch. Loose fill compresses over time, so plan on installing more than that at the start and topping it up regularly.
Coverage chart
How many square feet one unit of mulch covers at each depth:
| Depth | 1 cubic yard | 2 cu ft bag | 3 cu ft bag |
|---|---|---|---|
| 1 inch | 324 sq ft | 24 sq ft | 36 sq ft |
| 2 inches | 162 sq ft | 12 sq ft | 18 sq ft |
| 3 inches | 108 sq ft | 8 sq ft | 12 sq ft |
| 4 inches | 81 sq ft | 6 sq ft | 9 sq ft |
Bags or bulk: when does delivery pay off?
One cubic yard is 13.5 bags of 2 cubic feet. To compare, multiply the bag price by 13.5 and set it next to the bulk price per yard plus delivery. If bags cost $4.50, a yard of bagged mulch costs about $61. If bulk mulch sells for $40 a yard and delivery is a flat fee, bulk wins once you need a few yards. The calculator does this math for you when you enter both prices.
| Bagged | Bulk | |
|---|---|---|
| Best for | Small beds, touch-ups, tight access | New beds, big yards, several yards of mulch |
| Handling | Fits in a car; easy to carry where you need it | Dumped in one pile; you move it by wheelbarrow |
| Leftovers | Unopened bags keep for next season | An extra half-yard pile has to go somewhere |
Topping up old mulch
Mulch breaks down, so most beds need a refresh every year or two, but not a full new layer. Push a trowel into the bed and measure what’s left. If you have 1.5 inches and your target is 3, enter 1.5 as the depth in the calculator. Rake the old layer first to break up any crust so water can soak through.
Common mulch types
| Type | Good to know |
|---|---|
| Shredded hardwood | Knits together and stays put on gentle slopes |
| Pine bark nuggets | Attractive and long-lasting, but large nuggets can float away in heavy rain |
| Pine needles (pine straw) | Needles interlock and stay in place; good around acid-loving plants |
| Wood chips | Inexpensive, sometimes free from tree services; small chips break down fast |
| Shredded leaves | Free; shred them first so they don’t mat into a layer water can’t get through |
Planning a path with stone instead? The gravel calculator works the same way and adds tons. For beds with curves or several sections, find the total area with the square footage calculator and use the “I know the area” option above.
Frequently asked questions
How many bags of mulch are in a yard?
13.5 bags of 2 cubic feet, or 9 bags of 3 cubic feet. A cubic yard is 27 cubic feet.
How much area does a yard of mulch cover?
About 108 square feet at 3 inches, 162 square feet at 2 inches, or 324 square feet at 1 inch.
Can mulch be too deep?
Yes. Layers much thicker than about 4 inches can keep water and air from reaching plant roots, and they stay soggy against stems and trunks. In beds, stick to 2–3 inches and top up rather than piling on.
How many bags of mulch do I need for a 10 × 10 area?
At 3 inches deep, a 100 sq ft area needs 25 cubic feet: 13 bags of 2 cubic feet (12.5 rounded up), or 9 bags of 3 cubic feet. That’s just under one cubic yard.
