Mulch calculator for Washington
Plan bed quantities in yards or bags, with depth notes for plant health.
Enter your project dimensions
Each cubic yard contains 27 cubic feet, equal to exactly 13.5 garden-center bags holding 2-cubic-foot bags. This conversion is the main purpose of the calculator. Add your bed measurements and selected depth below to see the bulk cubic-yard requirement alongside its bag equivalent, giving you numbers for a store comparison. Shredded hardwood is light at around 600 lb per yard, which is why mulch is sold by volume and bulk delivery concerns volume, not weight.
Calculating mulch for landscape beds
- In feet, measure every bed and combine the totals. For round beds, enter the diameter, then use circle mode to calculate the area.
- For an existing layer, select 2 inches; use 3 inches on a new or bare bed. At more than 4 inches, roots can begin to lose oxygen.
- The calculation provides cubic yards for bulk ordering, plus a store-bag comparison based on 13.5 bags per yard.
Bags (2 cu ft) = cubic yards × 13.5
Coverage guide
| Depth | 1 cubic yard covers | 10 bags (2 cu ft) cover |
|---|---|---|
| 1 inch | 324 sq ft | 240 sq ft |
| 2 inches | 162 sq ft | 120 sq ft |
| 3 inches | 108 sq ft | 80 sq ft |
| 4 inches | 81 sq ft | 60 sq ft |
Common order amounts
| Project | Typical size | Depth | Cubic yards | ≈ Bags |
|---|---|---|---|---|
| Foundation beds along the house | 40 x 3 ft | 3" | 1.1 yd³ | 15 bags |
| Four tree rings | 4 ft across each | 3" | 0.5 yd³ | 6 bags |
| All beds, average yard | ≈ 500 sq ft | 3" | 4.6 yd³ | 63 bags |
| Annual refresh of the same beds | ≈ 500 sq ft | 1.5" | 2.3 yd³ | 31 bags |
| Playground surface | 15 x 15 ft | 6" | 4.2 yd³ | 56 bags |
Comparing bulk mulch and bags
Ten bags marks the point where the choice changes. Bags suit smaller amounts, while bulk is generally less expensive above that amount. Free delivery also removes the need to rent a truck. After bringing home 15 bags, the difference is easy to see. Have one yard delivered, cover any remaining material with a tarp, and the job is finished.
Plant-safe mulch depths
- After raking last year's mulch loose, apply 2 inches over that layer.
- Apply 3 inches over exposed ground. It suppresses weed seeds and helps the soil stay moist through July.
- Leave a clear ring 3-6 inches between tree bark and mulch. Material against the trunk can rot bark and shelter rodents. Keep the mulch shaped as a flat donut, not a volcano.
- Limit mulch to 4 inches in all locations. A deep layer that stays wet can deprive roots of air.
- Use playground-certified chip, not landscape shred, for play areas, with a depth of at least 6 inches.
Selecting mulch types
This calculator uses shredded hardwood by default. It interlocks well and tends to stay put on gentle slopes. Chips and nuggets can remain in place for an extra season or two, but heavy rain can make them float and spread. Dyed mulch retains its color but breaks down more slowly. Each material uses the same volume calculation, so type affects appearance and replacement timing, not the quantity ordered.
Preparing for delivery
Three yards of mulch makes a small-car-sized pile. Reserve about one parking space on the driveway, place a tarp for the delivery, and remember that shredded mulch can stain new concrete. Get it spread before a week or two has passed. After a month in a large pile, the material can heat internally and turn sour. Plan on 30 to 45 minutes of wheelbarrow time for each yard, saving the last half-yard for overlooked beds near the garage.
Common mulch quantity questions
How many mulch bags equal a cubic yard?
What is the cubic-foot volume of a yard of mulch?
How much mulch is needed?
What coverage comes from one yard of mulch?
What does one yard of mulch weigh?
What is the price of a yard of mulch?
Can mulch attract termites?
Can fresh mulch be applied over old mulch?
More calculators
Avoid filling a 27-bag cart.
Order bulk shredded hardwood by the yard for driveway delivery, free of charge.
