Figure out how much mulch your beds need before a trip to the garden center. Add each bed as a rectangle, circle, or triangle — split odd shapes into pieces — choose a depth, and get the total in cubic yards and cubic metres, plus the number of 1.5, 2, and 3 cubic foot bags. Enter prices to see whether bags or a bulk delivery works out cheaper for your yard.
Building new beds first? The topsoil calculator sizes the soil underneath, and the gravel calculator covers rock beds and paths. Laying a new lawn next to the beds? Try the sod calculator. Everything runs in your browser.
Frequently asked questions
How deep should mulch be?
Two to four inches suits most garden beds. Fine, shredded mulch holds together well at 2 to 3 inches; coarse bark nuggets and wood chips need 3 to 4 inches to suppress weeds. Deeper than about 4 inches can starve roots of oxygen and keep the soil too wet, while less than 2 inches lets weeds through. If you are refreshing an existing bed, an inch or so on top of the old layer is usually enough — rake the old mulch first and measure what is still there before ordering.
How many bags of mulch are in a cubic yard?
A cubic yard is 27 cubic feet, so it equals 13.5 two-cubic-foot bags or 9 three-cubic-foot bags. One cubic yard covers about 324 square feet at 1 inch deep, 162 square feet at 2 inches, 108 square feet at 3 inches, and 81 square feet at 4 inches. Bags are sold by volume, not weight, so a bag of wet mulch and a bag of dry mulch cover the same area. The calculator rounds bag counts up, since you cannot buy part of a bag.
Is bulk mulch cheaper than bags?
For anything beyond a few small beds, usually yes. Bulk mulch from a landscape yard often costs a fraction of the per-yard price of bagged mulch, but it comes with a delivery fee and is normally sold in whole or half yards. Bags win for small jobs, for hard-to-reach backyards where you would otherwise wheelbarrow a pile, and when you want a specific dyed or specialty product. Enter a bag price, a bulk price, and the delivery fee, and the calculator shows which option costs less for your area.
How do I mulch around a tree?
Spread mulch in a wide, flat ring — ideally out to the drip line — at 2 to 4 inches deep, and keep it 3 to 6 inches away from the trunk. Piling mulch up against the bark in a cone, sometimes called volcano mulching, keeps the trunk wet, encourages rot and disease, gives rodents cover to chew the bark, and can cause girdling roots. To size a tree ring, choose Circle and enter the outside diameter of the ring; the small bare circle at the trunk makes no practical difference to the total.