Mulch Calculator
Estimate how much mulch you need by area and depth — plus bags and total cost. Switch between imperial and metric units.
Mulch Calculator
Estimate how much you need — and the cost.
- cubic feet 25
- cubic meters 0.708
- tons (US) 0.37
- tonnes 0.34
Quick coverage reference
1 cubic yard covers about 324 sq ft at 1 in deep / about 108 sq ft at 3 in deep; one 2 cu ft bag covers about 12 sq ft at 2 in deep.
How it's calculated
- Wood mulch bulk density runs about 400–800 lb/cu yd (bark is light; wet or composted mulch is heavier); we use the upper-typical 800 for weight estimates.
- Garden guidance is 2–4 in: 3 in is most common for beds (retains moisture, suppresses weeds), up to 4 in around trees, 2 in for annual flower beds.
Source: inchcalculator.com/mulch-calculator/ (density & coverage figures cross-checked)
How much mulch do I need?
Mulch is sold by volume — in bulk by the cubic yard, or in bags (usually 2 cubic feet each). To find how much you need, multiply the bed's area by the depth of the layer you want, then convert to cubic yards.
The math is simple: cubic yards = area (sq ft) × depth (in) ÷ 324. The 324 comes from the fact that one cubic yard, spread one inch deep, covers 324 sq ft. So a single cubic yard covers about 108 sq ft at the typical 3-inch depth. Enter your bed size above and the calculator handles the conversion, plus how many 2 cu ft bags that works out to.
How to measure for mulch
Measure each bed
Length × width for rectangular beds. For a round bed or a mulch ring around a tree, switch the area shape above to Circle or Border and enter those measurements instead.
Choose a depth
Most beds get 3 inches. Use 2 inches for annual flower beds and up to 4 inches around trees and shrubs.
Read your result
The calculator returns cubic yards plus the number of 2 cu ft bags. Switch to metric any time with the toggle.
Add a little extra
Order about 5–10% more than the exact figure to cover settling and uneven ground.
Mulch depth & buying tips
Bagged mulch is convenient for small jobs, but bulk by the cubic yard is usually cheaper once you need more than about 3 cubic yards (≈ 20 bags).
2–4 inches suppresses weeds and holds moisture. Piling it deeper — or against trunks — can suffocate roots and invite rot.
Organic mulch breaks down over a season. Most gardens need a 1-inch refresh each year rather than a full replacement.
Mulch calculator FAQ
How many bags of mulch are in a cubic yard?
A cubic yard is 27 cubic feet, so it equals about 13.5 bags of the standard 2 cu ft size (round up to 14).
How deep should mulch be?
Aim for 2–4 inches. Three inches is the sweet spot for most beds — enough to block weeds and retain moisture without smothering plants.
How much does a yard of mulch cover?
One cubic yard covers about 324 sq ft at 1 inch deep, 162 sq ft at 2 inches, or 108 sq ft at the common 3-inch depth.
How much does a cubic yard of mulch weigh?
Wood mulch is light — roughly 400–800 lb per cubic yard depending on type and moisture. Wet or composted mulch sits at the heavier end.
Should I remove old mulch first?
Usually no. If the existing layer is still 1–2 inches thick, just top it up to your target depth rather than removing and replacing it.