Mulch Calculator
Estimate how much mulch you need, and compare the cost of bags with bulk delivery.
Results
| Item | Value |
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Quick Answer
Multiply length by width by depth in feet to get cubic feet, then divide by 27 for cubic yards. A 20 ft by 10 ft bed at 3 inches deep needs 50 cubic feet, which is 1.85 cubic yards or 25 bags of 2 cubic feet each.
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Table of Contents
How This Mulch Calculator Works
Mulch is sold by the bag or in bulk by the cubic yard. This calculator works out the volume of your bed, then shows how many bags you need and what each option could cost.
Quick explanation: Cubic feet = length × width × depth in inches ÷ 12.
- Depth: the layer of mulch, in inches.
- Bag size: many bags hold 2 cubic feet, but check the label.
- Prices: optional, to compare bags with bulk.
Core Formulas
- Area: length × width
- Cubic feet: area × depth in inches ÷ 12
- Cubic yards: cubic feet ÷ 27
- Bags: cubic feet ÷ bag size, rounded up
One cubic yard is 27 cubic feet, because 3 ft × 3 ft × 3 ft = 27.
Worked Example
Your bed is 12 ft by 8 ft, and you want 2 inches of mulch from 2 cubic foot bags.
- Area = 96 sq ft
- Volume = 96 × 2 ÷ 12 = 16 cu ft
- Cubic yards = 16 ÷ 27 = 0.59 cu yd
- Bags = 16 ÷ 2 = 8 bags
Planning Your Mulch
- Depth: check advice for your plants and mulch type.
- Trunks and stems: keep mulch from piling up against them.
- Bulk delivery: larger areas are often cheaper in bulk, but check the delivery fee.
- Odd shapes: split the bed into rectangles and add the results.
Frequently Asked Questions
Multiply length, width and depth in feet to get cubic feet. Divide by 27 for cubic yards, or by your bag size for bags.
A cubic yard is 27 cubic feet, so it takes 13.5 bags of 2 cubic feet, or 14 if you round up.
At 3 inches deep, a cubic yard covers 108 square feet.
It depends on your local prices and delivery fees. Enter both prices above to compare.
Yes. Split the bed into rectangles, run each one, and add the results.
References & Sources
| Source | Used For | Link |
|---|---|---|
| NIST, Unit conversion | US customary length and volume units. | https://www.nist.gov/pml/owm/metric-si/unit-conversion |
| Wikipedia, Cubic yard | A cubic yard equals 27 cubic feet. | https://en.wikipedia.org/wiki/Cubic_yard |