Mulch Calculator

Calculate mulch, gravel, or stone needed for landscaping. Get cubic yards, bags, weight, and cost comparison for rectangle, circle, or triangle beds.

Something wrong or missing? Tell us — we read every report and fix issues fast.

How to Calculate Mulch

Select your bed shape, enter dimensions and depth, then the calculator does the rest. The formula varies by shape:

Rectangle: Area = Length × Width
Circle: Area = π × (Diameter ÷ 2)²
Triangle: Area = Base × Height ÷ 2

Volume in cubic yards = Area (sq ft) × Depth (inches) ÷ 324. The overage factor adds extra to account for waste, settling, and uneven ground.

Recommended Depths

2 inches: Light refresh of existing beds
3 inches: Standard coverage for most beds (most common)
4 inches: New beds or heavy weed suppression
6 inches: Pathways with heavy foot traffic

Never apply mulch deeper than 4 inches around plants. Excessive depth suffocates roots and traps moisture, causing rot.

Coverage Chart (per cubic yard)

2" deep: 162 sq ft
3" deep: 108 sq ft
4" deep: 81 sq ft

A standard 2 cu ft bag covers about 8 sq ft at 3 inches deep. One cubic yard equals roughly 13.5 bags.

Bulk vs Bagged Mulch

Bagged ($3-8 per bag): Convenient for small beds under 200 sq ft, easy to transport and store
Bulk ($30-120 per cubic yard): 30-50% cheaper for large projects, delivered by truck

For areas over 200-300 sq ft, bulk is almost always more economical. The calculator compares both options and labels the cheaper one as "Best value." A cubic yard of mulch weighs 400-800 lbs depending on material and moisture content.

Measuring Irregular Shapes

For beds that aren't a clean rectangle, circle, or triangle:

Break it up: Divide complex beds into simpler shapes. Calculate each separately and add the totals.
Curved beds: Use the circle shape for round beds, or approximate with a rectangle using the widest and longest measurements.
Corner beds: A triangle works well for wedge-shaped beds along a fence corner or wall intersection.

Choosing the Right Material

Shredded bark: Best all-around. Affordable, stays in place, decomposes to enrich soil
Wood chips: Longer lasting than bark. Better for pathways than garden beds
Pine straw: Naturally acidic — great for azaleas, blueberries, and rhododendrons
Rubber mulch: Permanent, doesn't decompose. Best for playgrounds, not gardens
Pea gravel: Decorative with excellent drainage. Won't decompose or attract pests
River rock: Permanent solution, no annual replacement. Retains heat in summer

Application Tips

Keep mulch 3-6 inches away from tree trunks and plant stems — build a donut shape, not a volcano
Organic mulch needs refreshing every 1-2 years as it decomposes
Best time to buy: mid-spring to early summer when stores run promotions (up to 40% off)
Lay landscape fabric underneath for extra weed suppression, especially with rock or gravel
Top up annually when depth drops below 2 inches

Related Calculators

Slope Percentage Calculator — % Grade, Angle, Ratio Calculate slope percentage from rise and run, or convert between percent grade, degrees, and 1:N ratio. Includes ADA ramp, driveway, road, and drainage standards. Acreage Calculator — Land Area in Acres, Hectares Calculate land area in acres from length and width. Converts to sq ft, hectares, sq m, and more. Square Yards Calculator — Carpet, Flooring, Cost Calculate square yardage from length and width. Includes unit conversion and optional cost estimation for carpet and flooring. Square Footage Calculator — Room Area + Paint Estimate Calculate square footage for rooms and spaces. Get paint and flooring estimates from one entry. Paint Calculator — Coats, Doors, Windows, Cost Calculate paint and primer needed with custom door/window dimensions, ceiling toggle, and cost estimates. Flooring Calculator — Multi-Room with Pattern Waste Calculate flooring for multiple rooms with waste presets by pattern (straight/diagonal/herringbone) and box/carton calculator.

Frequently Asked Questions

How much does a yard of mulch cover?

One cubic yard of mulch covers about 162 sq ft at 2 inches deep, 108 sq ft at 3 inches, or 81 sq ft at 4 inches. To find yards needed, multiply the bed area in square feet by depth in inches and divide by 324. Add 10% for spillage and settling, or 15 to 20% for curved beds.

How deep should mulch be?

Mulch should be 2 to 3 inches deep when refreshing existing beds and 3 to 4 inches deep for new beds. Avoid going over 4 inches, because deeper mulch can suffocate plant roots. Wood mulch decomposes and usually needs a fresh top-up every year, while rubber mulch and stone last much longer.

How many bags of mulch are in a yard?

One cubic yard of mulch equals about 13.5 bags of the standard 2 cubic foot size. Each 2 cu ft bag holds about 0.074 cubic yards. To convert, multiply cubic yards by 13.5 to get bags, or divide bags by 13.5 to get cubic yards. Round up, since stores do not sell partial bags.

Is it cheaper to buy mulch in bulk or bags?

Bulk mulch is usually cheaper for areas of about 500 sq ft or more, while bags suit small beds. A 500 sq ft bed at 3 inches deep needs about 4.6 cubic yards, which is roughly 63 bags of 2 cu ft each. Bags are easier to transport and store, but bulk delivery saves money at that size.