Mulch Calculator — Beds, Bags, Bulk & Cost
Plan mulch for multiple garden beds, subtract existing layers and stock, then compare whole bags with bulk delivery using your quotes.
2.315 yd³ to buy · 32 bags or 2.5 yd³ bulk
Editable example: a 25 × 10 ft bed, 3 inches of new mulch, no existing layer, no allowance or stock. Bags hold 2 ft³; bulk is sold in 0.5 yd³ increments. Prices are not entered.
Each example replaces the whole plan, including quotes.
Your beds and mulch depth
Replace this example with your measurements. Use the same mulch product across these beds; plan different products separately. Target depth is a total layer, not an extra layer.
Switching units preserves the original measurements. Edit a converted value only if you want to change the plan.
Stock and purchase sizes
Compare your bag and bulk quotes
How much mulch do I need?
For each bed, calculate its area and subtract paths or other excluded areas. Multiply that net area by the depth still needed: target total depth minus the existing layer, with a minimum of zero. Add the bed volumes, apply your optional allowance, then subtract mulch you already have.
With feet and inches: cubic feet = square feet × added inches ÷ 12. Divide cubic feet by 27 for cubic yards. With metric measurements: cubic metres = square metres × added centimetres ÷ 100. Rectangle area is length × width; circle area is π × diameter² ÷ 4.
Worked example: 250 square feet at 3 inches
250 × 3 ÷ 12 = 62.5 cubic feet, or about 2.315 cubic yards. A 2-cubic-foot bag gives 62.5 ÷ 2 = 31.25 bags, rounded up to 32. Those bags contain 64 cubic feet, leaving 1.5 cubic feet after covering the planned area. Bulk sold in half-yard increments rounds up to 2.5 cubic yards, leaving 5 cubic feet.
Bags or bulk: which costs less?
The comparison uses the actual rounded order. Bag total = whole bags × bag price + bag delivery or collection cost. Bulk total = ordered volume × price per chosen volume unit + bulk delivery. Include taxes and other charges in your quotes if you want them in the comparison. There is no universal volume at which bulk becomes cheaper.
Blank means unknown; 0 means free. A lower-cost recommendation appears only when both material prices and both delivery costs are supplied. No purchase is needed when your existing layer and stock cover the requirement.
What depth should I use?
Choose a depth appropriate to the mulch material, plants and site, following local horticultural guidance. The default 3 inches is a calculation example, not a recommendation for every planting. Measure the current layer and avoid double-counting it. This calculator does not determine a safe depth around trunks or stems.
Why can the order exceed the calculated volume?
Bags are bought whole. Bulk suppliers may have a minimum order and sell only in set increments. This planner applies both limits, and shows leftover material separately from your optional allowance. Confirm the supplier’s minimum, increment and bag-label volume before ordering.
Accuracy and limitations
Circle areas use an approximation of π. Irregular beds, slopes, uneven depth, settlement and measurement error affect actual coverage. Split irregular areas into simple shapes without overlapping them. The planner estimates loose volume, not weight, delivery vehicle capacity or installation labor. Displayed volumes are rounded, but purchase counts use the underlying values.
Volume method: University of California Agriculture and Natural Resources mulch guide. Prices and purchasing limits come from your supplier, not this guide.
