Mulch Calculator — Free Online Mulch Estimator

How to Use the Mulch Calculator

1. Enter the area to cover: Measure the total square footage of all garden beds, tree rings, and landscaped areas where you plan to apply mulch. For rectangular beds, multiply length by width. For circular tree rings, measure the radius and use the formula pi times radius squared. Add all individual areas together and enter the total. Our square footage calculator can help with complex shapes.
2. Set the mulch depth: Enter your desired mulch depth in inches. The most common depth is 3 inches, which provides excellent weed suppression and moisture retention. Use 2 inches for fine mulches like shredded leaves or for refreshing existing mulch. Use 4 inches for coarse bark nuggets or for areas with severe weed pressure. Never exceed 4 inches around plants.
3. Enter bulk pricing: Input the current price per cubic yard for bulk mulch delivery in your area. Typical bulk prices range from $25 to $50 per cubic yard depending on mulch type and location. Call your local landscape supply yard for current pricing, as costs fluctuate seasonally with highest prices in spring.
4. Enter bag pricing: Input the price per bag for standard 2 cubic foot bags from your local home improvement store. Prices typically range from $3.50 to $6.00 per bag. The calculator automatically compares bulk versus bag costs and shows which option saves you more money.

Results instantly display the total volume in cubic yards and cubic feet, the number of 2 cubic foot bags needed, and a cost comparison between bulk and bagged mulch so you can make the most economical purchasing decision.

Mulch Calculation Formula

Variables Explained

• Area: The total square footage of ground to be covered with mulch. Measure each bed separately and add the areas together. Include pathways only if you plan to mulch them as well.
• Depth: The thickness of the mulch layer in inches, divided by 12 to convert to feet for the volume calculation. The standard recommended depth is 3 inches for most organic mulches.
• Cubic Yards: The total volume divided by 27 (since 1 cubic yard = 27 cubic feet). This is the unit used by landscape supply companies for bulk mulch orders and pricing.
• Bag Count: The total cubic feet divided by 2 (the volume per standard bag). Results are rounded up to whole bags since partial bags cannot be purchased.

Step-by-Step Example

Suppose you have 500 square feet of garden beds to mulch at 3 inches deep, with bulk mulch at $35 per cubic yard and bags at $4.50 each:

1. Calculate cubic feet: 500 x (3 / 12) = 500 x 0.25 = 125 cubic feet
2. Convert to cubic yards: 125 / 27 = 4.63 cubic yards
3. Calculate bags: 125 / 2 = 63 bags
4. Bulk cost: 4.63 x $35 = $162.04
5. Bag cost: 63 x $4.50 = $283.50

Buying in bulk saves $121.46 compared to bags for this project. At nearly 5 cubic yards, bulk delivery is clearly the better value. The break-even point for this pricing would be around 2 cubic yards (about 26 bags).

Practical Examples

Example 1: Nancy's Front Yard Landscaping

Nancy has three front yard beds totaling 350 square feet: two foundation beds (80 sq ft each) and a large island bed (190 sq ft). She wants 3 inches of shredded hardwood mulch at $38 per cubic yard bulk or $4.25 per bag:

• Cubic feet: 350 x 0.25 = 87.5 ft³
• Cubic yards: 87.5 / 27 = 3.24 yd³
• Bags: 87.5 / 2 = 44 bags
• Bulk cost: 3.24 x $38 = $123.12
• Bag cost: 44 x $4.25 = $187.00

Nancy orders 3.5 cubic yards of bulk mulch, saving about $64 compared to buying 44 bags. The bulk delivery is dumped in her driveway, and she spreads it with a wheelbarrow and garden rake over one afternoon.

Example 2: Greg's Small Backyard Beds

Greg has two small raised beds in his backyard totaling 80 square feet. He wants 2 inches of cedar mulch. Bulk cedar costs $52 per yard, while bags cost $5.50 each:

• Cubic feet: 80 x (2/12) = 13.3 ft³
• Cubic yards: 13.3 / 27 = 0.49 yd³
• Bags: 13.3 / 2 = 7 bags
• Bulk cost: 0.49 x $52 = $25.48 (plus $50 delivery fee)
• Bag cost: 7 x $5.50 = $38.50

For this small project, buying 7 bags at $38.50 is far cheaper than bulk delivery at $75.48 (including the delivery fee). Greg picks up the bags during a regular trip to the home improvement store, saving both money and hassle.

Example 3: Diana's Entire Property

Diana is mulching her entire property: front beds (400 sq ft), side beds (200 sq ft), backyard beds (600 sq ft), and tree rings (150 sq ft), totaling 1,350 square feet at 3 inches deep. Bulk mulch costs $30 per yard:

• Cubic feet: 1,350 x 0.25 = 337.5 ft³
• Cubic yards: 337.5 / 27 = 12.5 yd³
• Bags: 337.5 / 2 = 169 bags
• Bulk cost: 12.5 x $30 = $375
• Bag cost: 169 x $4.50 = $760.50

Diana saves $385.50 by ordering bulk delivery. She orders 13 cubic yards to round up and schedules two deliveries on consecutive weekends to avoid having a massive pile in her driveway for too long.

Mulch Reference Table

Bulk cost calculated at $35/yd³. Bag count based on standard 2 cubic foot bags. Actual prices vary by mulch type and location.

Tips and Complete Guide

Choosing the Right Mulch Type

Organic mulches like shredded bark, wood chips, pine straw, and composted leaves decompose over time, enriching the soil with nutrients and improving soil structure. Hardwood bark mulch is the most popular residential choice, offering a clean appearance and moderate decomposition rate at $30 to $45 per cubic yard. Pine bark nuggets resist compaction and float less in heavy rain. Cypress mulch naturally repels insects but has raised environmental concerns about unsustainable harvesting. Cedar mulch has a pleasant aroma and natural insect-repelling properties. For vegetable gardens, straw or shredded leaves are ideal because they decompose quickly, feeding the soil and beneficial organisms. Dyed mulches (red, black, brown) use iron oxide or carbon-based dyes that are generally safe for gardens but check for recycled wood content that may contain contaminants.

Proper Mulch Application Techniques

Begin by removing weeds and old, matted mulch from the bed. Edge the beds cleanly with a half-moon edger or spade to create a defined border that keeps mulch in place. If weed pressure is severe, lay landscape fabric before mulching, though be aware that fabric can impede water and nutrient penetration over time. Spread mulch evenly to the desired depth using a garden rake, maintaining a consistent layer across the entire bed. Create a slight depression around the base of shrubs and perennials rather than mounding mulch against stems. For trees, apply mulch in a wide ring extending to the drip line, keeping it 3 to 6 inches away from the trunk. Water the mulch lightly after application to help it settle and prevent it from blowing away in wind.

Benefits of Mulching for Plant Health

Mulch provides numerous benefits that promote healthier plants and reduce maintenance. A 3-inch layer of organic mulch reduces soil moisture evaporation by 25% to 50%, significantly reducing watering frequency during hot summer months. Mulch moderates soil temperature, keeping roots cooler in summer and warmer in winter, reducing stress on plants during temperature extremes. Weed suppression from mulch eliminates competition for water and nutrients, while also reducing the need for herbicides. As organic mulch decomposes, it adds humus to the soil, improving structure, drainage, and microbial activity. These combined benefits result in healthier, more vigorous plants with less ongoing maintenance effort.

Common Mistakes to Avoid

• Creating mulch volcanoes around trees: Piling mulch against tree trunks causes bark rot, encourages girdling roots, and attracts boring insects. Always maintain a 3 to 6-inch gap between mulch and the tree trunk.
• Applying mulch too deep: More than 4 inches of mulch can suffocate plant roots by blocking oxygen and water penetration. Excessive depth also creates a habitat for rodents and can cause fungal growth. Stick to 2 to 3 inches for most applications.
• Using fresh wood chips around small plants: Freshly chipped wood temporarily depletes nitrogen from the soil surface as it begins to decompose. Use aged or composted wood chips around flower beds, or top-dress with a nitrogen fertilizer to compensate.
• Ignoring existing mulch depth: Each year, homeowners often add a fresh layer without considering what remains from previous years. Scrape back existing mulch to check the current depth before adding more. The total depth should never exceed 4 inches.
• Mulching too close to the house foundation: Organic mulch against the foundation creates moisture conditions favorable to termites and carpenter ants. Maintain at least a 6-inch gap of bare soil or inorganic material between mulch and the foundation.

Frequently Asked Questions