Mulch Calculator - Calculate Cubic Yards for Landscaping

About this calculator

Calculate how much mulch you need for your landscaping project. Estimate cubic yards and bags of mulch for garden beds, trees, and flower beds with depth.

How to use

Enter your values in the fields above and click Calculate to see your results. Click Clear to reset all fields.

What it is and when to use it

This calculator turns bed geometry into a mulch order. Instead of guessing "a few bags," you enter the actual shapes in your yard — a rectangular border, a circular ring around a tree, a triangular corner bed, or a lump-sum square footage from a site plan — and it adds up the total area, then converts that area into cubic yards and bags at three common depths. It's built for the planning stage of a landscaping project: sizing a delivery order from a bulk supplier, budgeting for bagged mulch from a home center, or comparing the cost difference between the two before you buy.

Use it any time you're refreshing beds, mulching around trees, or starting a new planting area and need a number to bring to the store or the phone with a supplier. Because the tool supports rectangles, circular tree rings (with an inner radius to subtract the trunk), triangles, and a direct square-footage entry, you can combine several bed shapes in one calculation rather than running the numbers separately and adding them by hand.

The formula, explained

The calculator first finds total bed area in square feet, then converts it to volume at a chosen depth:

• Rectangle area = Length × Width.
• Circular bed area = π × Outer radius², minus π × Inner (trunk) radius² if you're mulching a ring around a tree trunk.
• Triangle area = 0.5 × Base × Height.
• Total area is the sum of every shape you fill in, plus any extra square footage you enter directly.

The calculator reports results at 2", 3", and 4" depths side by side, since those are the depths most commonly recommended for mulch, and highlights the 3" figure for the cost estimate because 2–3 inches is the depth most nurseries and extension services recommend for weed suppression and moisture retention without smothering roots.

Worked example

Say you have a single rectangular bed 20 ft long and 10 ft wide (200 sq ft), mulch costs $45 per cubic yard in bulk or $4.25 per bag, and you want the standard 3" depth:

• Total area: 20 × 10 = 200 sq ft.
• At 3" depth: 200 × (3 ÷ 12) = 50 cubic feet = 50 ÷ 27 ≈ 1.85 cubic yards, or 25 bags (50 ÷ 2, rounded up).
• Bulk cost: 1.85 cu yd × $45/cu yd ≈ $83.33.
• Bagged cost: 25 bags × $4.25/bag = $106.25.

For comparison, the same 200 sq ft bed needs about 1.23 cu yd (17 bags) at 2" depth, or 2.47 cu yd (34 bags) at 4" depth — entering these numbers into the calculator above reproduces all three depths at once.

Common mistakes and how to interpret the result

• Measuring outside edges only: for curved or irregular beds, measure the actual planted area, not the outer border of pavers or edging, or you'll overbuy.
• Forgetting to subtract the trunk: when mulching a ring around a tree, always fill in the inner radius — skipping it overstates the area by the full circle of the trunk zone.
• Assuming bulk and bagged mulch settle the same: bagged mulch is often slightly more compacted than bulk, so bag counts from big-box retailers can vary a little from the calculator's 2 cu ft assumption — check the bag label.
• Ignoring settling over time: mulch compresses 10–20% over a season; if you're topping up existing beds rather than starting fresh, a 2" refresh depth is usually enough instead of a full 3".

Frequently Asked Questions

Common Tip Percentages

General Household Budget Ratios (50/30/20 Rule)

Common Measurement Conversions for Everyday Use