Mulch Calculator — Cubic Yards and Bag Counts
Convert a rectangular planting-bed area and target mulch depth into bulk cubic yards and common retail bag counts.
What does the mulch calculator calculate?
Find mulch by multiplying bed area by depth, converting cubic feet to cubic yards, and adding waste for settling and irregular edges. This calculator also shows equivalent 2- and 3-cubic-foot bags. Keep mulch clear of trunks and foundations, and follow plant-specific depth recommendations.
Mulch cubic-yard formula
Bed area becomes volume when multiplied by depth in feet. Dividing by 27 converts cubic feet to bulk cubic yards; bag equivalents use the same waste-adjusted cubic feet.
How to measure for an accurate estimate
- Measure planting beds inside edging and divide curved borders into short average-width sections.
- Subtract broad areas occupied by patios, dense groundcover, ponds, or other non-mulched surfaces.
- Check existing mulch depth in several places and enter only the additional depth required.
- Calculate islands separately, then add the results before applying any supplier delivery minimum.
Front foundation bed
A 30 ft by 6 ft bed receives 3 in of mulch plus 10% for settling and waste.
The estimate is 49.5 ft³, or 1.83 yd³, equal to 25 two-ft³ bags or 17 three-ft³ bags.Before you purchase material
- Compare delivered bulk mulch with total bag cost at the calculator’s equivalent volumes.
- Inspect mulch composition and aging; color alone does not establish product suitability.
- Avoid piling mulch against tree trunks, plant crowns, siding, or drainage openings.
- Schedule delivery on a surface that can hold the pile without staining or blocking runoff.
Common questions
How many bags of mulch equal one cubic yard?
One cubic yard contains 27 cubic feet. That equals 13.5 two-cubic-foot bags or nine three-cubic-foot bags, before waste. Since stores sell whole bags, round 13.5 up to 14 when buying two-cubic-foot packages for a full yard.
How deep should mulch be?
Depth depends on mulch type, plant needs, soil conditions, and existing material. A moderate layer can suppress weeds and reduce evaporation, while excessive depth may retain unwanted moisture or bury crowns. Follow local extension and plant-specific guidance for the selected mulch.
Should old mulch be removed before adding more?
Not automatically. Measure what remains and inspect for matting, contamination, disease concerns, or excessive buildup. Often the existing layer can be loosened and topped up only enough to restore the desired depth. Keep total accumulated depth within horticultural guidance.
Does mulch settle after installation?
Yes. Particle size, moisture, handling, and decomposition can reduce apparent depth. The default 10% allowance helps with settling and minor placement losses, but it is not exact. Ask the supplier about expected yield and avoid compensating with an excessively deep layer.
Sources and reference standards
- U.S. EPA WaterSense — Landscaping TipsFederal recommendations for water-efficient landscape planning and soil preparation.
- National Institute of Standards and Technology — SI Units: VolumeFederal reference for volume units and unit relationships.