Mulch Calculator

Calculate mulch volume and bags needed for landscaping projects. Supports different mulch types and depth recommendations.

Mulch Calculator

Calculate how much mulch you need for your landscaping project

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Fill in the project details to calculate your mulch needs

Depth Guidelines by Application

Fine Mulch (1-2"):

Compost, grass clippings, pine needles

Flower Beds (2-3"):

Most flowering plants and perennials

Trees & Shrubs (2-4"):

Around woody plants, extend to drip line

Pathways (3-4"):

Wood chips for walking areas

Frequently Asked Questions

How deep should mulch be?

Standard mulch depth is 2-3 inches for most landscaping per Mulch & Soil Council recommendations. Pathways and high-traffic areas need 3-4 inches. New beds benefit from 3 inches initially. Annual top-dressing adds 1-2 inches. Depths over 4 inches can suffocate plant roots and retain excess moisture.

How do I convert cubic yards to bags of mulch?

One cubic yard equals 27 cubic feet. Standard 2 cubic foot bags: 13.5 bags per yard. Standard 3 cubic foot bags: 9 bags per yard. To calculate bags needed: multiply cubic yards by 13.5 for 2-cu-ft bags or by 9 for 3-cu-ft bags.

What's the 324 rule for mulch calculation?

The 324 rule states: 1 cubic yard covers 324 square feet at 1 inch deep. For 2 inches: divide by 2 (162 sq ft per yard). For 3 inches: divide by 3 (108 sq ft per yard). This provides quick estimates: a 100 sq ft bed at 3 inches needs approximately 0.93 cubic yards.

How much does a cubic yard of mulch weigh?

Dry hardwood mulch weighs 400-800 pounds per cubic yard. Dry bark mulch weighs 300-500 pounds per yard. Wet mulch weighs significantly more: 800-1,200 pounds per yard. Cedar mulch is lighter at 300-400 pounds per yard. Weight affects delivery costs and handling requirements.

Industry Standards Referenced

Last verified: November 2025

Mulch & Soil Council (MSC) Standards(UVPG - Uniform Voluntary Product Guidelines)

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National trade association standards for horticultural mulch producers. Maintains certification program with lab analysis, quality control, and product guidelines ensuring consistent, safe mulch products.

Key Requirements:

  • •Product labeling: Accurate volume, material source, and composition disclosure
  • •Quality standards: Free from contaminants, weed seeds, and foreign materials
  • •Certified products: Lab-tested for consistency, pH balance, and safety
  • •Material specifications: Minimum particle size distribution standards
  • •CANM certification: Certified All-Natural Horticultural Mulches program (2025 standards)
Applies to:Commercially produced mulch products

ASTM F1292 - Playground Surfacing Impact Attenuation(ASTM F1292)

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Standards for impact-absorbing playground surfaces including mulch. Specifies minimum depths based on equipment fall height to prevent serious head injuries. Critical safety standard for playground mulch installations.

Key Requirements:

  • •Fall height ≤4 feet: 6 inches engineered wood fiber (EWF) minimum
  • •Fall height 4-8 feet: 9 inches EWF minimum depth
  • •Fall height 8-12 feet: 12 inches EWF minimum depth
  • •Compression testing: Regular testing required, replenish as settles
  • •ADA accessibility: 1:16 max slope, wheelchair-accessible surface required
  • •Use zone coverage: Mulch must extend 6 feet in all directions from equipment
Applies to:All public and commercial playground installations

ASTM F2075 - Engineered Wood Fiber for Playground Surfacing(ASTM F2075)

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Specifications for engineered wood fiber (EWF) used in playgrounds. Defines particle size distribution, wood species, contaminants, and installation requirements for safety surfacing.

Key Requirements:

  • •Particle size: 95% must pass 1-inch screen, defined size distribution
  • •Wood source: Hardwood preferred, no treated lumber, no painted wood
  • •Contaminants: Maximum 1% foreign material by weight
  • •Installation depth: Based on critical fall height per F1292
  • •Maintenance: Monthly inspection, annual depth checks, replenish as needed
Applies to:Commercial playground wood fiber safety surfacing

University Extension Service Guidelines(State Agricultural Extension Offices)

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Regional land-grant university recommendations for mulch depth, material selection, and application timing based on local climate and plant types. Provides science-based gardening guidance.

Key Requirements:

  • •Depth recommendations: 2-4 inches typical, varies by plant and climate
  • •Material selection: Match mulch to plant needs (acid-loving vs. alkaline)
  • •Application timing: Spring after soil warms, fall for winter protection
  • •Keep away from stems: 3-6 inch clearance from woody plants prevents rot
  • •Annual replacement: Organic mulches decompose, replenish annually or biannually
Applies to:Home gardening and landscape mulching practices

National Association of Landscape Professionals (NALP) Standards(Professional Installation Best Practices)

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Industry standards for professional mulch installation including preparation, material selection, application methods, and maintenance schedules.

Key Requirements:

  • •Bed preparation: Remove weeds, edge beds, install landscape fabric if specified
  • •Depth standards: 2-4 inches ornamental beds, 3-4 inches trees/shrubs
  • •Stem clearance: 3-6 inches clear around woody stems (volcano mulching harmful)
  • •Slope considerations: Thinner application on slopes (2 inches max), prevent washout
  • •Maintenance cycle: Annual or biannual replenishment as material decomposes
Applies to:Professional landscape installation and maintenance

EPA Guidelines - Yard Trimmings and Compost Mulch(EPA Sustainable Materials Management)

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Federal guidelines promoting yard waste recycling into mulch and compost. Encourages municipalities to provide composted mulch as alternative to landfill disposal.

Key Requirements:

  • •Compost maturity: Minimum 60-90 days composting before use
  • •Temperature: Thermophilic composting (131-170°F) kills weed seeds and pathogens
  • •Quality standards: Stable, finished compost with earthy smell, no odors
  • •Contaminant screening: Remove plastics, metal, and non-compostable materials
  • •Municipal programs: Many cities offer free or low-cost compost mulch
Applies to:Composted yard waste mulch and municipal programs

Standards Disclaimer: Standards and codes are subject to periodic updates. Always verify current requirements with local building authorities and professional engineers before beginning construction. Links provided are for reference only.

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Want to Learn More?

Mulch & Soil Council standards with the 324 rule (1 yd³ = 324 sq ft at 1 inch), depth recommendations, and material weights.

Read the Mulch Calculator Guide

How to Use This Calculator

  1. Measure bed area: Enter length and width of landscape beds.
  2. Select mulch depth: 2-3 inches for beds, 3-4 inches for playgrounds.
  3. Choose mulch type: Hardwood, cedar, pine bark, or rubber.
  4. Review volume: See cubic yards for bulk or bags (2 cu ft) needed.

Mulch Depth Recommendations

Standard landscape beds: 2-3 inches. Weed suppression: 3-4 inches. Playground safety surfaces: 6-12 inches depending on fall height per ASTM F1292.