Mulch calculator
Measure your tree ring and leave a clear center around the trunk. We’ll do the volume math.
6.87 cubic feet · 0.25 cubic yards
Using 2 cubic foot bags, rounded up.
Measure existing mulch first. This estimates a uniform layer, with no extra allowance for settling.
The method, without the mystery
Ring area = π × (outer diameter² − clear center diameter²) ÷ 4. Multiply by depth in feet to get cubic feet. Divide by 27 for cubic yards, or by the bag volume and round up for whole bags.
Keep the trunk clear
Mulch belongs over soil, not piled against bark. Keep the root flare visible, and account for material already on the ground before adding more. The default depth is an example, not a prescription for every site or material.
Irregular rings, slopes, compaction, and moisture change the amount you actually use. Check the finished depth as you spread the material.
Read the planting guide for root-flare and establishment advice. Reference: University of Minnesota Extension .