Mulch Calculator
A mulch calculator works out how much mulch you need by multiplying your bed area by the mulch depth, giving a volume in cubic yards, then converting to bags. Mulch is sold by the cubic yard in bulk or in 2 cubic foot bags. Enter your bed dimensions and depth below.
depth in inches; standard bag = 2 cubic feet; 13.5 bags per cubic yard.
- 2 cu ft bags
- 0
- Estimated cost
- $0.00
Enter your dimensions to see the result.
Estimate only. Material yields and prices vary by supplier and region; confirm before ordering.
How Do You Calculate How Much Mulch You Need?
To calculate mulch, multiply the length by the width of your bed to get the area, then multiply by the depth in feet to get cubic feet, and divide by 27 for cubic yards. To get bags, divide the cubic feet by 2, since a standard mulch bag holds 2 cubic feet. A 20 by 8 foot bed at 3 inches deep is 40 cubic feet, about 1.48 cubic yards, or 20 bags. The calculator does this instantly.
How Many Bags of Mulch Are in a Cubic Yard?
There are 13.5 bags of mulch in a cubic yard, since a cubic yard is 27 cubic feet and a standard bag holds 2 cubic feet. This is the crossover point for buying: above about 7 to 10 bags, bulk mulch by the cubic yard is usually cheaper and means fewer trips, while bags suit small beds. The calculator shows both so you can choose.
How Deep Should Mulch Be?
Mulch is usually applied 2 to 3 inches deep. Two inches suppresses weeds and retains moisture for established beds, while 3 inches gives fuller coverage and longer life. Going much deeper than 3 inches can suffocate roots, so depth has a practical ceiling. Set 2 to 3 inches in the calculator depending on whether you are topping up or laying fresh mulch.
What Type of Mulch Should You Calculate For?
Most mulch is calculated the same way by volume, whether it is wood chips, bark or shredded hardwood, because coverage depends on depth not material. Rubber mulch is the exception in pricing and weight, so it has its own calculator below. For wood mulches, the main calculator works for any type, since you are filling a volume regardless of the species.
Calculators in this family
How Do You Calculate Mulch Needed?
Formula
Cubic Yards = Area (sq ft) x Depth (ft) / 27; Bags = Cubic Yards x 13.5 (for 2 cu ft bags)
- Measure the bed area in square feet.
- Choose a depth (2 to 3 inches) and convert to feet by dividing by 12.
- Multiply area by depth for cubic feet, then divide by 27 for cubic yards.
- Multiply cubic yards by 13.5 for the number of 2 cubic foot bags.
Worked example
A 200 sq ft bed at 3 inches deep: 3 / 12 = 0.25 ft; 200 x 0.25 = 50 cubic feet; 50 / 27 = about 1.85 cubic yards; 1.85 x 13.5 = about 25 of the 2 cubic foot bags.
- Use 3 inches for new beds and weed control, 2 inches for topping up.
- Bulk mulch by the yard is usually cheaper than bags once you need more than about 5 or 6 bags.
See how much mulch you need (reference table by area and depth)
Frequently asked questions
- How much mulch do I need for a 20x8 bed?
- A 20 by 8 foot bed at 3 inches deep needs about 1.48 cubic yards of mulch, or 20 standard 2 cubic foot bags. At 2 inches deep it needs about 1 cubic yard, or 13 bags.
- How many bags of mulch in a cubic yard?
- There are 13.5 standard 2 cubic foot bags in a cubic yard. Above roughly 10 bags, bulk mulch is usually cheaper and means fewer trips.
- How deep should mulch be?
- Mulch is usually 2 to 3 inches deep. Two inches suppresses weeds, 3 inches gives fuller coverage, and more than 3 inches can suffocate plant roots.
- How much does a yard of mulch cover?
- One cubic yard of mulch covers about 160 square feet at 2 inches deep, or about 108 square feet at 3 inches deep. Coverage drops as depth increases.
- How do you calculate how many bags of mulch you need?
- Find your cubic yards (area times depth in feet, divided by 27), then multiply by 13.5 for 2 cubic foot bags. A 200 square foot bed at 3 inches deep needs about 25 bags.