Mulch calculator
Related Tools
About Mulch calculator
This mulch calculator converts bed dimensions and desired depth into cubic yards, cubic feet, and bag counts — covering rectangular, circular, and triangular garden beds. Enter length (or diameter), width, depth in inches, and the number of identical beds; the calculator instantly shows how many cubic yards to order in bulk and how many 2 cu ft or 3 cu ft bags to buy at a garden center. It supports both regular wood/bark mulch and rubber mulch, with an on-page depth guide so you can apply the right thickness the first time. All math runs locally in your browser — nothing is uploaded.
How to calculate how much mulch you need
The formula is straightforward: multiply your bed's area (in square feet) by the depth in feet. For a 10 ft × 8 ft bed at 3-inch depth, that is 10 × 8 × 0.25 = 20 cubic feet. Divide by 27 to get cubic yards (≈ 0.74 yd³) or divide by 2 or 3 to get bag counts (10 or 7 bags respectively). For circles, use π × radius². For triangles, use ½ × base × height. This calculator handles all three shapes and shows all outputs at once so you can compare bulk vs. bagged pricing.
Wood mulch vs. rubber mulch — which should you use?
Wood mulch (shredded bark, wood chips, straw) decomposes over one to three seasons, adding organic matter to soil — ideal for garden beds, shrub borders, and vegetable garden paths. Rubber mulch lasts 10–15 years without decomposing, repels insects, and does not harbor mold, making it the top choice for playground fall zones, dog runs, and low-maintenance landscapes. Rubber mulch also drains faster and retains less moisture, which matters in wetter climates. Both types suppress weeds when applied at the right depth.
Key Features
- Rectangle, circle (by diameter), and triangle bed shapes
- Outputs cubic yards (bulk delivery), cubic feet, and bag counts for 2 cu ft and 3 cu ft bags
- Adjustable depth in inches — with recommended depth guide on-screen
- Multiply by number of identical beds in a single calculation
- Rubber mulch mode with settling reminder
- Instant results as you type — no button click required
Use Cases
- Ordering bulk mulch delivery — get the exact cubic-yard quantity before calling a supplier
- Buying bagged mulch at a garden center — know the bag count before you load the cart
- Mulching flower beds, tree rings, shrub borders, and vegetable garden paths
- Rubber mulch for playground fall zones, dog runs, and low-maintenance landscapes
- Estimating cost when comparing bulk vs. bagged mulch prices
Pro Tips
- 1 cubic yard = 27 cubic feet. Most bulk mulch is sold by the cubic yard; bagged mulch is typically sold as 2 or 3 cubic foot bags.
- A standard recommendation is 2–3 inches for flower beds and 3–4 inches around trees and shrubs. Deeper mulch suppresses weeds better but can trap too much moisture against plant stems.
- Add a 10–15% waste buffer for uneven ground, edges, or spillage — especially for large beds or rubber mulch that compacts over time.
- Rubber mulch for playgrounds is typically installed at 6 inches to meet ASTM F1292 impact-attenuation standards for fall height.
- Keep all mulch at least 2 inches away from plant stems and tree trunks to prevent rot and pest issues.
Frequently Asked Questions
How many cubic yards of mulch do I need?
Multiply the bed length (ft) × width (ft) × depth (ft), then divide by 27 to convert to cubic yards. For example, a 10 ft × 8 ft bed at 3 inches deep = 10 × 8 × (3/12) = 20 cubic feet ÷ 27 ≈ 0.74 cubic yards. This calculator does that math instantly for rectangular, circular, and triangular beds.
How many bags of mulch do I need for a given area?
Divide total cubic feet by the bag size. A 10 ft × 8 ft bed at 3 inches needs ≈ 20 cubic feet. That is 10 bags of 2 cu ft mulch, or 7 bags of 3 cu ft mulch (always round up). The calculator shows both bag sizes simultaneously.
What is the recommended mulch depth?
The standard recommendation is 2–3 inches for annual flower beds, 3 inches for perennials and shrubs, and 3–4 inches around trees (keeping mulch 2 inches from the trunk). Rubber mulch for playgrounds typically requires 6 inches per ASTM F1292. Deeper mulch suppresses weeds more effectively but can cause moisture and root problems if piled against stems.
How do I calculate rubber mulch for a playground?
Use this calculator with the Circle or Rectangle shape, set depth to 6 inches (ASTM F1292 standard for common fall heights), and enter your play area dimensions. Rubber mulch is denser than wood mulch, so add 10–15% extra to account for settling. The calculator shows cubic yards for bulk orders and bag counts if buying bagged rubber mulch.
Is bulk mulch cheaper than bagged mulch?
Generally yes — bulk mulch delivered by the cubic yard is typically 20–40% cheaper per cubic foot than bagged mulch from garden centers. The trade-off is a minimum delivery quantity (often 1 cubic yard) and the need to wheelbarrow it from the drop point. Use this calculator to find the total cubic yard amount, then compare local bulk vs. bag prices.
Does AllOneTools store my measurements?
No. The mulch calculator runs entirely in your browser. Your dimensions are never sent to any server, consistent with the privacy model of all AllOneTools calculators.