Mulch Calculator
Enter your bed's area and how deep you want the mulch to find cubic yards and bag counts.
Example
For a 120 sq ft bed at 3 inches deep: 120 × 3 ÷ 12 = 30 cubic feet, which is 30 ÷ 27 ≈ 1.11 cubic yards, or 15 standard 2-cu-ft bags.
How it works
Volume in cubic feet = area (sq ft) × depth (in) ÷ 12. Cubic yards = cubic feet ÷ 27, and bags = cubic feet ÷ 2 (rounded up for standard 2-cu-ft bags).
Good to know
The Mulch Calculator turns three simple measurements — the area of your bed in square feet, how deep you want the mulch, and the size of the bags you plan to buy — into the volume of mulch you actually need. It reports the answer three ways at once: cubic yards (for ordering bulk loads), cubic feet (the raw volume), and the number of bags rounded up to the next whole bag. It's built for home gardeners, landscapers pricing a job, and anyone trying to avoid a second trip to the garden center.
Reach for it before a planting weekend or a spring bed refresh, when you know roughly how big an area you're covering but don't want to guess how many bags fit in the cart. The bag-size field is the part that makes it flexible: most retail bags are 2 cubic feet, but many stores sell 1.5- or 3-cubic-foot bags, so set it to match what's actually on the shelf and the bag count stays honest.
Reading the result is straightforward, but pick the number that matches how you're buying. Use the cubic-yards figure if a supplier delivers bulk mulch by the yard, and use the bags figure for bagged product. Because bags are always rounded up, you'll usually end up with a little extra — that's intentional, since beds settle unevenly and you rarely want to come up short.
- Measure odd-shaped beds in sections, add the square footage together, then enter the total area.
- For new beds, lean toward 3 inches; for topping up existing mulch, 1 to 2 inches is often enough.
- Keep mulch pulled back from trunks and stems rather than piling it against them.
Frequently asked questions
How deep should I spread mulch?
Most garden beds use 2 to 3 inches of mulch for weed control and moisture retention. Around trees and shrubs, 3 to 4 inches works well, but keep mulch a few inches away from trunks and stems.
How many bags are in a cubic yard?
One cubic yard equals 27 cubic feet, so it takes about 14 standard 2-cubic-foot bags to equal one cubic yard. Buying in bulk by the cubic yard is usually cheaper for large areas.
Is my data uploaded anywhere?
No — this calculator runs entirely in your browser. Your inputs never leave your device, and it works offline once loaded.
Is this calculator free?
Yes, completely free with no sign-up and no limits.
People also ask
How do I calculate square footage of a garden bed?
For a rectangular bed, multiply length by width in feet. For irregular shapes, break the area into rectangles or circles, calculate each, and add them together before entering the total.
How much does a cubic yard of mulch cover?
One cubic yard equals 27 cubic feet, so it covers about 108 square feet at 3 inches deep, roughly 162 square feet at 2 inches, or about 324 square feet at 1 inch.
How much does a yard of mulch weigh?
Weight varies by material and moisture, but dry wood mulch typically runs about 400 to 800 pounds per cubic yard. Wet or dense mulches like compost can weigh considerably more.
What is the best depth for mulch around plants?
A general range is 2 to 4 inches depending on the area and material; too little allows weeds through, while too much can hold excess moisture against roots and stems. Conditions vary by plant and climate.
Is it cheaper to buy mulch in bags or in bulk?
For large areas, bulk mulch sold by the cubic yard is usually cheaper per cubic foot than bagged mulch, though bags are more convenient for small jobs and easier to transport in a car.
How often should mulch be replaced?
Organic mulch breaks down over time and is commonly topped up once a year, often in spring. You typically add a thin refresh layer rather than removing and replacing the entire bed.
Can I use this calculator for soil or compost instead of mulch?
Yes, the volume math is identical for any material spread by area and depth, so it works for topsoil, compost, or similar. Just be aware that suggested depths and bag sizes differ by material.
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