Mulch Calculator

How much mulch do you need? Enough to make the neighbors think you have your life together.

Use this free mulch calculator to find how many cubic yards of mulch you need for garden beds, tree rings, or landscaping. Enter the area in square feet and your target depth in inches and get the volume in cubic yards — the unit landscapers, bulk suppliers, and the guy with the dump truck actually use.

Mulch is sold by the cubic yard in bulk and by the 2- or 3-cubic-foot bag at the store, which means every mulch project involves a unit conversion at the worst possible moment. We do the conversion. You do the spreading. One of these involves a shovel.

What This Mulch Calculator Does

• Converts area × depth into cubic yards of mulch
• Defaults to a 3-inch depth, the standard for weed suppression and moisture retention
• Tells you how many bags that equals (see the formula notes) so you can compare bulk vs bagged
• Works for wood mulch, bark, straw, rubber mulch, compost, and topsoil — volume is volume

How to Use the Mulch Calculator

Inputs:

• Area — bed area in ft². Rectangles: length × width. Circles (tree rings): 3.14 × radius². Add up multiple beds
• Depth — in inches. 2–3" for most beds; 3–4" around trees and shrubs; 1–2" when topping up existing mulch

Steps:

1. Measure and total your bed areas in square feet
2. Choose a depth (3" is the default sweet spot)
3. Click Calculate for cubic yards
4. Bulk: order that many yards (round up to the half yard). Bagged: multiply yards by 13.5 for 2 ft³ bags or 9 for 3 ft³ bags

How the Calculation Works

Cubic Yards = (Area ft² × Depth in ÷ 12) ÷ 27 1 yd³ = 27 ft³ = 13.5 bags (2 ft³) = 9 bags (3 ft³)

• Depth ÷ 12 converts inches to feet, giving cubic feet; ÷ 27 converts to cubic yards
• Quick rule: 1 cubic yard covers ~100 ft² at 3 inches (or 160 ft² at 2", 80 ft² at 4")
• Bulk mulch is usually much cheaper per yard than bags once you need more than ~1 yard; bags win for small beds and no-truck situations

Worked Example: Two beds 4 × 25 ft, plus a 10-ft-diameter tree ring, at 3 inches

1. Beds: 2 × (4 × 25) = 200 ft² · Tree ring: 3.14 × 5² = 78.5 ft² → total ≈ 278 ft²
2. Cubic feet = 278 × (3 ÷ 12) = 69.5 ft³
3. Cubic yards = 69.5 ÷ 27 = 2.57 yd³ → order 3 yards bulk
4. In bags: 2.57 × 13.5 ≈ 35 bags of 2 ft³. Thirty-five bags. In a sedan. Get it delivered.

Tips (From People Who Have Made These Mistakes)

• Keep mulch 2–3 inches away from tree trunks and plant stems — "mulch volcanoes" rot bark and invite pests
• Pull weeds and lay cardboard or landscape fabric first if the bed is a mess; mulch suppresses weeds, it does not exorcise them
• A bulk yard of hardwood mulch weighs 400–800 lb depending on moisture. A pickup bed holds about 2 yards. Your back holds less
• Refreshing existing beds? 1–2 inches on top is enough; total depth over 4 inches starves roots of oxygen

Frequently Asked Questions

Mini Roast Disclaimer

We roast the number, not you. The mulch will look incredible for about three weeks, and then nature resumes.

Reality Check

The estimate assumes level beds and even spreading. Sloped beds, uneven ground, and settling (mulch compacts ~10–20% in the first month) can change how far a yard goes. Order a little extra for bulk, or plan a top-up. And measure the beds — guessing "about 200 square feet" is how people end up with 4 extra yards on the driveway.