Results update as you type. Round up when ordering.
Based on 2 and 3 cu ft bags, the common bagged mulch sizes. Check the bag label.
Formula checked against manufacturer specs
Rounded up to whole units
Runs in your browser
Mulch formula
Cubic feet = area (sq ft) × depth (in) ÷ 12. Divide by 27 for cubic yards. One cubic yard covers about 108 sq ft at 3 inches, or 162 sq ft at 2 inches.
How deep should mulch be?
University extension services generally recommend 2–4 inches of organic mulch. Less than 2 in lets weeds through; more than 4 in can starve roots of oxygen. Keep mulch a few inches away from tree trunks—avoid “mulch volcanoes.”
Bags or bulk?
Bagged mulch is usually sold in 2 cu ft bags (13.5 bags = 1 cu yd). Above roughly 2–3 cubic yards, bulk delivery from a landscape yard is usually cheaper per yard.
Measuring irregular beds
Split the bed into rectangles (L × W), triangles (½ × base × height) and circles (3.14 × radius²) and add the areas.
It uses the standard formula shown on this page and rounds bags, boxes and pieces up to whole units. Product sizes vary by brand, so confirm with the label or your supplier before you buy.
Should I buy extra material?
Yes. A 5–10% allowance covers cuts, spills and uneven surfaces; running short mid-job usually costs more than a few leftovers.
Is this calculator free?
Yes. Every PorchMath calculator is free, needs no account and runs entirely in your browser.