Enter the size of your bed and how deep you want the mulch. The calculator shows cubic yards, cubic feet, and bag counts. It works for bark, wood chips, straw, and compost.
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How to use the mulch calculator
- Pick a rectangle, a circle, or enter your total area
- Measure the length and width of the bed
- Enter the mulch depth
- Read your total in cubic yards and bags.
For an odd-shaped bed, split it into rectangles and circles. Add the areas together. Then pick “I know my area” and enter the total.
Mulch coverage chart
One cubic yard of mulch is 27 cubic feet. Here is how far each amount spreads.
| Depth | 1 cubic yard covers | One 2 cu ft bag covers | One 3 cu ft bag covers |
|---|---|---|---|
| 1 in | 324 sq ft | 24 sq ft | 36 sq ft |
| 2 in | 162 sq ft | 12 sq ft | 18 sq ft |
| 3 in | 108 sq ft | 8 sq ft | 12 sq ft |
| 4 in | 81 sq ft | 6 sq ft | 9 sq ft |
How deep to spread mulch
Spread 2 to 3 inches in vegetable and flower beds. Use 3 to 4 inches of wood chips on paths and around shrubs.
Keep mulch a few inches away from tree trunks and plant stems. Mulch piled against bark holds moisture and invites rot.
Fine mulch like shredded leaves or compost packs down. A layer of 1 to 2 inches is enough. Coarse wood chips stay loose, so they can go deeper.
Which mulch to use
Straw works well in vegetable gardens and breaks down by the end of the season. Buy straw, not hay. Hay carries weed seeds.
Shredded bark and wood chips last longer. They suit perennial beds, shrubs, and paths.
Shredded leaves and compost are free if you make them yourself. They feed the soil as they break down.
Pine straw suits acid-loving plants like blueberries. It also stays in place on slopes.
When to mulch
Mulch in late spring once the soil warms up. Mulch laid on cold soil keeps it cold longer. In fall, a fresh layer protects roots and perennials over winter.
Planting first? My plant spacing calculator shows how many plants fit in your bed. You can also find perennials, shrubs, and groundcovers for your zone on Select-A-Plant.
Where I buy mulch, soil, beds, and seeds
Mulch
- Bark mulch on Amazon: Shredded bark lasts a long time in perennial beds and around shrubs.
- Pine straw mulch on Amazon: Pine straw stays loose and suits acid-loving plants.
Compost
- Organic compost on Amazon: Mix compost into your bed or spread it as a mulch.
Raised beds
- Epic Gardening metal raised beds: Epic Gardening sells the metal raised beds I recommend. My code HOMEFORTHEHARVEST5 takes 5% off.
Seeds
- Botanical Interests: My favorite seed company. Each packet has growing notes printed inside.
Questions about mulch
How many bags of mulch are in a yard?
One cubic yard equals 13.5 bags of 2 cubic feet or 9 bags of 3 cubic feet.
How much area does a yard of mulch cover?
One cubic yard covers 108 square feet at 3 inches deep. At 2 inches deep, it covers 162 square feet.
Do I remove old mulch before adding new mulch?
No. Old mulch breaks down and feeds the soil. Rake it loose and add a fresh layer on top to reach your target depth.
More garden calculators
- Raised bed soil calculator shows how much soil to fill a bed
- Seed starting date calculator shows when to start seeds from your frost date
- Plant spacing calculator shows how many plants fit in a bed
- Last frost dates lists dates for major cities in the United States and Canada.