Mulch Calculator
Calculate mulch needed for landscaping, flower beds, and garden projects
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Typical: 2-3" for beds, 3-4" around trees
Double-shredded hardwood - most popular, long-lasting
Quick Answer
To calculate mulch: Length × Width × Depth (in inches) ÷ 324 = Cubic yards. One cubic yard covers about 108 sq ft at 3" deep. A 10×10 bed needs about 0.93 cubic yards.
Whether you're mulching flower beds, tree rings, or entire landscaped areas, this calculator helps you determine exactly how much mulch to order. Choose from different mulch types to get accurate coverage estimates in cubic yards or bags.
Dr. Snezana Lawrence
Mathematical Historian
15+ years experience
PhD from Yale University. Published mathematical historian ensuring precision in all calculations.
Education
PhD in Mathematical History - Yale University
Mulch Types & Benefits
| Type | Weight (lbs/cu ft) | Best For |
|---|---|---|
| Hardwood Mulch | 20 | Double-shredded hardwood - most popular, long-lasting |
| Cedar Mulch | 18 | Natural insect repellent, aromatic, long-lasting |
| Cypress Mulch | 22 | Resists decay and insects, holds color well |
| Pine Bark | 15 | Nuggets or shredded, acidifies soil slightly |
| Rubber Mulch | 45 | Long-lasting, playgrounds, no decomposition |
| Cocoa Shell | 25 | Chocolate scent, decorative, toxic to dogs |
Mulch Coverage Chart
| Depth | Sq Ft per Cu Yd | 2 cu ft Bags per 10 sq ft |
|---|---|---|
| 1 inch | 324 | 0.5 |
| 2 inches | 162 | 1 |
| 3 inches | 108 | 1.5 |
| 4 inches | 81 | 2 |
| 6 inches | 54 | 3 |
Recommended Depths by Application
| Application | Depth | Notes |
|---|---|---|
| Flower Beds | 2-3" | Keep away from plant stems |
| Tree Rings | 2-4" | Keep 6" from trunk, extend to drip line |
| Shrub Beds | 3-4" | Maintains moisture, suppresses weeds |
| Vegetable Gardens | 2-3" | Use straw or untreated wood |
| Pathways | 3-4" | Use heavier mulch to stay in place |
| Playgrounds | 6-12" | Rubber or engineered wood fiber |
Mulching Best Practices
- • Remove weeds and debris before mulching
- • Install landscape fabric for extra weed control (optional)
- • Keep mulch 2-3" away from plant stems and tree trunks
- • Don't pile mulch in "volcano" shapes around trees
- • Water the area after applying mulch
- • Top up mulch annually as it decomposes (1-2" layer)
- • Choose mulch color that complements your landscape
- • Consider wind exposure - heavier mulch stays put better
Frequently Asked Questions
How much mulch do I need?
Calculate: Length (ft) × Width (ft) × Depth (in) ÷ 324 = Cubic yards. For 100 sq ft at 3" deep: 100 × 3 ÷ 324 = 0.93 cubic yards.
How many bags of mulch do I need?
One cubic yard equals about 13.5 bags (2 cu ft each) or 9 bags (3 cu ft each). For 100 sq ft at 3" deep, you need about 12-13 bags (2 cu ft).
How deep should mulch be?
For most landscaping: 2-4 inches. Around trees: 2-3 inches, kept 6" from trunk. Playgrounds: 6-12 inches for safety.
How much area does a cubic yard of mulch cover?
At 2" depth: 162 sq ft. At 3" depth: 108 sq ft. At 4" depth: 81 sq ft per cubic yard.
How much does mulch weigh?
Organic mulch weighs 400-800 lbs per cubic yard depending on moisture. Dry hardwood: ~500 lbs/yard. Rubber mulch: ~1,200 lbs/yard.
How often should mulch be replaced?
Organic mulch should be topped up annually (1-2" layer) and fully replaced every 2-3 years. Rubber mulch lasts 10+ years.
Should I remove old mulch before adding new?
Not usually. Only remove if mulch is diseased, matted, or over 4" deep. Otherwise, rake existing mulch to break up and add new layer on top.
What is the best type of mulch?
Hardwood mulch is most popular for general landscaping. Cedar or cypress resist insects and decay. Pine bark acidifies soil for acid-loving plants.
Dr. Snezana Lawrence
Mathematical Historian | PhD from Yale
Dr. Lawrence is a published mathematical historian with a PhD from Yale University. She ensures mathematical precision and accuracy in all our calculations, conversions, and academic score calculators. Her expertise spans computational mathematics and educational assessment.
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