A mulch calculator takes the guesswork out of ordering. Enter your bed dimensions and desired depth, and you get cubic yards. Get it wrong and you’re making a second trip to the supply yard or staring at a leftover pile for a month.
Most homeowners guess on mulch orders. Most of the time, they guess wrong. This guide covers how the calculator works, coverage rates by mulch type, how to measure irregular beds, and two real-world jobs penciled out from start to finish.
Quick Answer: The Mulch Formula
The formula every contractor uses:
(Length in ft x Width in ft x Depth in inches) / 324 = Cubic Yards
The number 324 handles the unit conversion for you. It accounts for the 27 cubic feet in a cubic yard and the 12 inches in a foot.
Example: A bed that is 20 feet long, 10 feet wide, at 3 inches deep:
- 20 x 10 x 3 = 600
- 600 / 324 = 1.85 cubic yards (order 2 yards)
For multiple beds, calculate each one separately and add the totals.
If you’d rather skip the arithmetic entirely, plug your numbers into the mulch calculator. It handles the math and rounds up to a clean order quantity.
Mulch Types, Coverage Rates, and Pricing
Not all mulch covers the same. Texture, density, and how the material is shredded affects how far a cubic yard actually spreads. Finely shredded material settles tighter and covers slightly more area. Chunky bark nuggets have more air gaps and cover a little less.
Here are real coverage rates at 3 inches and current bulk pricing for 2026:
| Mulch Type | Coverage per Cu Yd at 3” | Bulk Price per Cu Yd | Lifespan |
|---|---|---|---|
| Hardwood (shredded) | 100-108 sq ft | $30-$45 | 1-2 years |
| Cedar | 100-108 sq ft | $40-$55 | 2-3 years |
| Dyed black | 100-108 sq ft | $35-$50 | 1-2 years |
| Dyed red | 100-108 sq ft | $35-$50 | 1-2 years |
| Dyed brown | 100-108 sq ft | $35-$50 | 1-2 years |
| Pine bark (mini nuggets) | 95-105 sq ft | $35-$45 | 1-2 years |
| Pine bark (large nuggets) | 85-95 sq ft | $40-$55 | 2-3 years |
| Cypress | 100-108 sq ft | $45-$60 | 2-3 years |
| Rubber (recycled) | 90-100 sq ft | $80-$120 | 10+ years |
Coverage rates are based on a consistent 3-inch spread. Use 324 as your divisor for all shredded types. For large nuggets with air gaps, some contractors use 300 instead of 324 to get a slightly more conservative estimate.
Why Lifespan Matters for Estimating
Hardwood runs $30-$45/yard and needs replacing every 1-2 years. Cedar is $40-$55 but lasts 2-3 years. Over 5 years, cedar often costs close to hardwood once you factor in delivery and labor for each refresh. Worth showing clients when they balk at the per-yard premium.
Rubber is a different calculation. The upfront cost is 2-3x higher, but it doesn’t decompose. For playgrounds or commercial paths where you need consistent cushion, the 10-year lifespan makes the math work. For garden beds, stick with wood. Rubber never breaks down, which means it never feeds the soil either.
Dyed vs. Natural Mulch
Dyed mulch costs roughly the same as hardwood. The color pops on day one and fades within 3-6 months. Commercial properties and high-curb-appeal residential jobs often request dyed black or red because it photographs well and looks sharp at season launch. Natural hardwood ages to a silver-gray that a lot of homeowners actually prefer over the faded artificial color.
Try EstimationPro free to build complete landscaping estimates with accurate material quantities, labor costs, and markup built in.
Depth Guide: 2, 3, and 4 Inches
Depth is the variable most people guess at. Each depth does something specific.
2 Inches
Coverage per cubic yard: about 162 sq ft
Best for refreshing existing beds that still have a solid layer underneath. Adding 2 inches on top of an existing inch brings total depth back to 3 inches without starting over. Two inches on bare soil does almost nothing for weed suppression. It looks nice for about three weeks, then the weeds push through.
3 Inches (The Standard)
Coverage per cubic yard: about 108 sq ft
This is the right answer for most jobs. New installations, established beds on bare soil, around shrubs and perennials. Thick enough to suppress weeds and hold moisture. Not so thick that plant roots can’t breathe. When someone asks what depth to use, 3 inches is the default.
4 Inches
Coverage per cubic yard: about 81 sq ft
For slopes with erosion concerns, pathways, or areas with serious weed pressure. You’ll use about 35% more material compared to 3 inches. One important rule at any depth: keep mulch 3-4 inches away from tree trunks and plant bases. Piling mulch against bark traps moisture and invites rot. This is the single most common mulching mistake on residential properties.
Coverage at Every Depth
| Depth | Coverage per Cubic Yard |
|---|---|
| 1 inch | 324 sq ft |
| 2 inches | 162 sq ft |
| 3 inches | 108 sq ft |
| 4 inches | 81 sq ft |
| 6 inches | 54 sq ft |
How to Measure Irregular Landscape Beds
Most beds aren’t clean rectangles. Here’s how to handle real-world shapes without overthinking it.
Curved beds: Break the bed into rough rectangles. Measure the length and average width of each section, calculate each one, and add the totals. You don’t need to hit it to the square foot. Being within 10% is close enough for ordering.
Circular beds around trees: Area = 3.14 x radius x radius. A mulch ring 8 feet in diameter (4-foot radius) covers: 3.14 x 16 = 50.3 sq ft. At 3 inches that’s about 0.46 cubic yards.
Irregular front yard beds: Walk the bed and mark out sections with stakes or flags. Measure each section’s longest and widest points, treat it as a rectangle, calculate, and sum. This method consistently gets you within 10% of actual, which is accurate enough.
The 10% rule: Always add 10% to your calculated volume before ordering. Beds aren’t perfectly flat, spreading involves some loss, and settling after a rain can leave thin spots. Calculate, add 10%, round up to the nearest half yard. That’s your order.
For complex areas where you need the geometry handled precisely, the square footage calculator helps work out irregular shapes before feeding the area into the mulch formula.
Bulk vs. Bagged: The Real Cost Comparison
This question comes up on almost every project. The short answer: buy bulk once you’re over 3 cubic yards. At smaller quantities, bags can be competitive depending on the delivery fee.
Bagged Mulch
- Standard bag size: 2 cubic feet
- Bags per cubic yard: about 13.5
- Retail price per bag: $3.50-$6.00
- Cost per cubic yard equivalent: $47-$81
Bags are useful for small touch-up jobs, tight spaces a truck can’t reach, or when you need a specific type not available locally in bulk. The tradeoff is real money plus the physical work of loading, transporting, and cutting open every bag.
Bulk Mulch
- Price per cubic yard: $30-$55 for wood types, $80-$120 for rubber
- Delivery fee: $50-$150 depending on distance
- Best for: any job over 3 cubic yards
The dump truck drops the pile at the end of the driveway. You wheelbarrow from there. Most yards require a 2-3 yard minimum for delivery.
Side-by-Side at 6 Cubic Yards
| Purchase Method | Cost Breakdown | Total |
|---|---|---|
| Bags (81 bags x $4.50) | No delivery fee | $364.50 |
| Bulk (6 yds x $40 + $75 delivery) | Materials + delivery | $315.00 |
At 6 yards the savings are already meaningful. At 10 yards you’re looking at $150-$200 in savings. At 20 yards, bulk beats bags by $400 or more. The math only gets better with volume.
Worked Example 1: Front Yard Landscape Beds
Scenario: Residential front yard refresh. Three separate beds around the foundation and driveway border. Homeowner wants hardwood mulch at 3 inches. Existing mulch has mostly decomposed.
Measurements:
- Bed 1 (foundation left): 24 ft x 4 ft
- Bed 2 (foundation right): 18 ft x 4 ft
- Bed 3 (driveway border): 35 ft x 3 ft
Calculations:
Bed 1: 24 x 4 x 3 / 324 = 0.89 cu yd
Bed 2: 18 x 4 x 3 / 324 = 0.67 cu yd
Bed 3: 35 x 3 x 3 / 324 = 0.97 cu yd
Total: 0.89 + 0.67 + 0.97 = 2.53 cubic yards
Add 10% buffer: 2.53 x 1.10 = 2.78, round up to 3 cubic yards
Cost at 3 yards:
- Material (3 yds x $38): $114
- Delivery fee: $65
- Total material cost: $179
At this quantity, bags are borderline competitive. Factor in the labor difference. Loading 40 bags beats a dump truck pile in tight-access situations, but 3 yards moves fast with a wheelbarrow on an open driveway.
Worked Example 2: Commercial Property Mulching
Scenario: Office park, 8 planting beds totaling 4,200 square feet. Manager wants dyed black mulch at 3 inches for uniform appearance. Full refresh, not a top-off. Delivery included in the supplier quote.
Calculation:
Total area: 4,200 sq ft at 3 inches
4,200 / 108 = 38.9 cubic yards
Add 10% buffer: 38.9 x 1.10 = 42.8 cubic yards, order 43 yards
Cost breakdown:
- Dyed black mulch at $45/yard x 43 yards: $1,935
- Delivery (included for 20+ yard order): $0
- Installation labor (43 yards x $35/yd installed): $1,505
- Total installed cost: $3,440
At that volume the supplier is often willing to negotiate. Getting the material down to $42/yard saves $129. A bulk discount to $40/yard saves $215. Worth asking before placing the order.
On refresh cadence: dyed black fades in 3-6 months. At this scale, a full refresh each spring plus a top-off in late summer is the realistic maintenance schedule.
For full landscaping estimates that include mulching alongside edging, planting, and seasonal cleanup, the landscaping cost calculator handles the full scope in one place.
When to Top Off vs. Full Refresh
This is a judgment call that affects both material cost and labor. Here’s how to think through it:
Top off (add 1-2 inches): Right call when existing mulch still has 1-2 inches of depth remaining. Restores weed suppression without starting over. Uses about half the material of a full refresh.
Full refresh: Necessary when mulch is matted and restricting water infiltration, when there’s fungal growth (artillery fungus, slime mold), when buildup is too deep, or when taking over a bed where you don’t know the history.
The easy test: Rake a finger through the existing mulch. If it loosens and you can see separate pieces, top off. If it compacts into a mat, remove it.
Timing: Spring before weeds germinate is the best window. Fall is second, where mulch insulates roots going into winter. Avoid mid-summer if possible.
Gravel vs. Mulch: When to Switch
Some clients ask about gravel or decorative stone instead of mulch. Gravel wins under AC units and equipment, in dry climates where wood breaks down too fast, and on high-traffic pathways. Mulch wins anywhere plants need soil amendment, on slopes where gravel rolls, and near hardscaping where a natural look matters.
The volume math is the same for both. The gravel calculator uses the same cubic yard formula and lets you line up both options side by side for a client comparison.
FAQs
How many cubic yards of mulch do I need for 1,000 square feet?
At 3 inches, 1,000 square feet needs about 9.3 cubic yards. Add 10% and order 10 yards. At 2 inches: 6.2 yards. At 4 inches: 12.3 yards.
How many bags of mulch equal a cubic yard?
About 13.5 standard 2-cubic-foot bags. Using 3-cubic-foot bags, you need about 9 per yard.
What is the coverage difference between hardwood and pine bark nuggets?
Shredded hardwood covers 100-108 sq ft per cubic yard at 3 inches. Large pine bark nuggets cover 85-95 sq ft at the same depth because of air gaps. Account for this when switching types mid-project.
Is rubber mulch worth the extra cost?
For playgrounds and commercial paths needing long-term cushion, yes. The 10-year lifespan at $80-$120/yard can beat replacing wood mulch every 1-2 years. For garden beds, no. Rubber doesn’t feed the soil.
How do I calculate mulch for a curved bed?
Break it into rough rectangles. Measure the longest and widest points of each section, calculate cubic yards for each, and add the totals. Within 10% of actual, which is close enough for ordering.
How often should I replace mulch?
Hardwood and dyed: every 1-2 years. Cedar and cypress: 2-3 years. Pine bark: 1-2 years small, 2-3 years large. Rubber: only top off if displaced. In wet climates like the Pacific Northwest, plan on refreshing more frequently than national averages suggest.
Should I remove old mulch before adding new?
Usually no. If existing mulch is below an inch, top it off. If it’s still 2 inches or more, rake it loose and add on top. Remove only if it’s matted, showing fungal growth, or piled so deep that adding more would push total depth past 5-6 inches.
Try EstimationPro free to build complete landscaping estimates with accurate material quantities, labor costs, and markup built in. Stop guessing on mulch orders and proposals.
Pricing in this guide reflects national averages for 2026. Actual costs vary by region, supplier, and season. Pacific Northwest markets typically see cedar and hardwood at the higher end of the ranges shown. Southeast and Midwest markets tend to be at or below mid-range. Get local quotes before finalizing any project budget.
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