How it works
Measure the bed, pick a depth, and get the exact amount to buy in yards or bags.
Measure the bed
Enter the length and width of the bed in feet. For odd shapes, break it into rectangles and add them.
Pick the depth
2–3 inches is the sweet spot for weed control without smothering plants.
Get yards & bags
Order bulk by the yard for big areas, or grab bags for small ones.
Bulk or bags — buying mulch the smart way
Mulch is sold two ways. Bagged mulch, usually in 2 cubic foot bags, is convenient for a bed or two. Bulk mulch, sold by the cubic yard and delivered in a pile, is much cheaper per unit once you need more than about ten bags. This calculator gives you both so you can see where the crossover is for your project.
The volume is length × width × depth. Because depth is in inches and the bed is in feet, divide the depth by 12 first, then divide the total by 27 to reach cubic yards. One cubic yard equals about 13.5 of those 2 cubic foot bags — so if the tool says two yards, that's roughly 27 bags, and a bulk delivery starts making sense.
Aim for a 2–3 inch layer. Thinner and weeds push through; much thicker and you can starve roots of water and air. Refresh the top inch each season rather than piling on a whole new layer every year.
Frequently asked questions
How much mulch for a 20×10 bed?
At 3 inches deep, about 1.85 cubic yards — roughly 25 bags of 2 cubic feet.
How many bags in a cubic yard?
About 13.5 bags of 2 cubic feet (round up to 14). Bulk is cheaper past ~10 bags.
How deep should mulch be?
2–3 inches. Less lets weeds through; more can suffocate roots.
How often should I replace it?
Top up the thinnest inch each spring rather than adding a full layer every year.
More material calculators
Estimates are for planning only. Confirm bag sizes and bulk pricing with your supplier before ordering.