Mulch & Topsoil Calculator
Determine bulk cubic yard volume and exact commercial bag counts for landscaping beds, raised garden planters, and topsoil grading. Includes automated 10% settlement factors.
How to Figure Out How Much Mulch You Need
Mulch and soil are ordered by the cubic yard in bulk and by the bag at retail. To work out how much mulch you need, measure the length and width of each bed in feet, choose a depth in inches, and the calculator above returns the cubic yards and bag counts, with a settling factor when you want one. The same volume math covers bark mulch, rubber mulch, pine straw, wood chips, and topsoil, so only the weight per yard changes. The sections below give the bag math, the right depth for each planting, material weights, and what it all costs.
The Volume-to-Bags Conversion Mathematics
A cubic yard of mulch is 27 cubic feet, which fills about 13.5 of the standard 2 cubic foot bags or 18 of the smaller 1.5 cubic foot bags. That is why bulk delivery pulls ahead of bagged mulch on any bed larger than a few yards.
The Imperial Baseline
[Area (sq ft) × (Depth in inches / 12)] / 27
The 324 Fast Multiplier
[Square Footage × Depth (in)] / 324
Retail Bag Mathematics
Based on 1 Cubic Yard = 27 Cubic Feet:
- 1.5 cu ft Bags: 27 / 1.5 = 18 Bags/yd³
- 2.0 cu ft Bags (Standard): 27 / 2.0 = 13.5 Bags/yd³
- 3.0 cu ft Bags: 27 / 3.0 = 9 Bags/yd³
Recommended Layer Depths by Horticultural Application
Annual Top-Dressing
Refreshing color on previously mulched beds where existing organic matter has not fully degraded. Prevents excessive smothering.
Veg & Annual Beds
Ideal aeration and weed control depth for delicate root systems, vegetable gardens, tomato planting, and shallow-rooted perennials.
Standard Shrub/Tree
The universal sweet spot for perennial beds, suppressing weed germination while retaining optimal summer soil moisture.
Weed Suppression Base
Applied over sheet mulching (cardboard weed barriers) or unplanted walkway borders.
Material Density, Texture & Compaction Allowances
| Ground Cover | Density (lbs/yd³) | Settling | Characteristics |
|---|---|---|---|
| Double-Shredded Hardwood | 600–800 | +10% | High moisture retention, mats together on slopes. |
| Pine Bark Nuggets / Fines | 450–600 | +5% | Acid-loving plants (azaleas, rhododendrons), slower breakdown. |
| Cedar Shreds | 500–650 | +8% | Natural insect deterrence, ideal for playground borders and walkways. |
| Screened Topsoil / Loam Blend | 2,000–2,200 | +15% to +20% | Lawn leveling and seedbed prep. |
| Raised Bed Mix (1:1:1) | 1,200–1,400 | +12% | Vegetable boxes and planter beds. (Soil/Compost/Peat) |
Topsoil, Fill Dirt, and Raised Beds
Soil is far heavier than bark, so order it by volume and keep an eye on the weight. A cubic yard of screened topsoil holds the same 27 cubic feet and weighs about 2,000 to 2,200 pounds, close to 1.1 tons, which is why a pickup carries one yard of soil but two or three yards of mulch. To find how much topsoil you need, use the same length by width by depth math as mulch.
- Raised garden beds: Fill to within 2 inches of the rim. A 4 by 8 foot bed at 12 inches deep takes about 1.2 cubic yards of a blended raised bed mix.
- Lawn top dressing: Spread a quarter to half an inch of screened compost or sandy loam. One cubic yard covers roughly 650 to 1,300 square feet at that depth.
- Fill dirt vs topsoil: Use cheaper fill dirt to bring up grade or backfill, then cap it with screened topsoil for anything you plan to plant.
What Mulch and Topsoil Cost
A bag of mulch runs about $3 to $7 for the standard 2 cubic foot size, so covering a full yard with bags costs roughly $40 to $95. Bulk bark delivered is usually $30 to $50 per cubic yard and pulls ahead of bags once you pass three or four yards. Screened topsoil runs about $20 to $50 per cubic yard in bulk. Dyed and premium blends sit at the top of each range, and delivery is a separate flat fee.
Take the cubic yards from the calculator, compare the bag total against a bulk load, and add delivery before you decide. Past about three yards, bulk almost always wins on price and on your back.
Authentic Landscaper & Homeowner FAQ
A 10×10 foot bed equals 100 square feet. At a recommended 3-inch depth, you need roughly 0.93 cubic yards (25 cubic feet). That requires approximately **13 bags** of standard 2.0 cu ft mulch (or 9 bags of 3.0 cu ft mulch).
Freshly shredded wood contains extensive air pockets between fibrous strands. Rain, overhead irrigation, and foot traffic cause particles to settle and interlock within 30 to 60 days, shrinking loose surface volume by 10% to 15%.
A mulch volcano occurs when mulch is piled directly against tree trunks in a steep cone. This traps persistent moisture against the bark, suffocates root flares, promotes fungal rot, and invites burrowing insects. Always leave a 3-to-4-inch clearance ring around tree trunks.
A cubic yard of dry topsoil weighs approximately 2,000 to 2,200 lbs (roughly 1.0 to 1.1 US tons), whereas a cubic yard of bark mulch weighs only 500 to 800 lbs. Standard pickup trucks can carry 2–3 yards of mulch, but only 1 yard of topsoil without exceeding axle payload ratings.
Fresh, un-aged wood chips rob surface nitrogen from the soil as soil microbes consume nitrogen to decompose raw carbon. For vegetable gardens and delicate flowers, use aged, composted bark mulch. Reserve fresh arborists' wood chips for perimeter paths and deep borders around mature trees.
A cubic yard is 27 cubic feet, so it takes 13.5 bags of 2 cubic foot mulch, 9 bags of 3 cubic foot mulch, or 18 bags of 1.5 cubic foot mulch. Going the other way, 60 bags of 2 cubic foot mulch is 120 cubic feet, which is about 4.4 cubic yards, and 4 yards of mulch is 54 of the 2 cubic foot bags or 36 of the 3 cubic foot size.
One cubic yard covers about 162 square feet at 2 inches deep, 108 square feet at 3 inches, and 81 square feet at 4 inches. So 2 yards of mulch covers roughly 216 square feet at the usual 3 inch depth for a shrub bed. Divide your square footage by those figures to get yards, or enter the bed size above and the calculator does it.