Mulch, Soil & Gravel Calculator
Calculate cubic yards of mulch, soil, or gravel from area and depth, plus bags needed and cost.
Published by Blueprint Dynamics. Planning tools, not professional advice. Read the formula, assumptions, and examples below before relying on a result. Independent professional review is not claimed. Learn more about our methodology →
AllTemplates • Blueprint Dynamics • hello@bpdynamics.io. Educational worksheet; entries and assumptions are not independently verified. This document is not tax, legal, medical, investment or engineering approval. Review current official rules and seek a qualified specialist where appropriate.
Scope and reference context
Material quantities assume the entered geometry and depth. Verify compaction, waste, drainage, delivery minimums and supplier coverage before ordering; prices are your inputs, not market quotes.
Primary reading context, not an endorsement or evidence that the linked organization reviewed this tool. No independent professional sign-off is claimed.
About the Mulch, Soil & Gravel Calculator
Bulk landscape materials are sold by the cubic yard, but every bed and border you measure comes in feet and inches, so the mental math trips up even experienced crews. This calculator bridges that gap: enter the length and width of the area in feet, the depth you want in inches, and the going price per cubic yard, and it returns the exact volume, an equivalent bag count, and the material cost. It handles mulch, screened topsoil, and gravel because all three are priced and delivered the same way even though their coverage goals differ.
Getting the volume right matters because delivery is the expensive part. A supplier will happily drop three yards when you only needed two, and you cannot return loose material once it is dumped on the driveway. Ordering a hair short is usually better than ordering long, since most yards let you grab a partial pickup load to top off. Use this tool before you call the supplier so the conversation is about scheduling, not guessing.
How the Mulch, Soil & Gravel Calculator works
The core formula converts your bed to a single volume: length in feet multiplied by width in feet multiplied by depth converted to feet (inches divided by 12), then divided by 27 because there are 27 cubic feet in a cubic yard. So volume in cubic yards = (length x width x depth/12) / 27. Depth is where people go wrong; three inches is 0.25 feet, not 3 feet.
Bag count assumes standard 2-cubic-foot bags, so the tool multiplies your cubic yards back into cubic feet (x27) and divides by 2, rounding up. Cost is simply cubic yards times your price per yard. Note the bag figure is there to help you compare bagged versus bulk pricing, not to suggest you buy 30 bags when a single bulk yard is cheaper by half.
Worked example
Say you are mulching a 20 ft by 12 ft foundation bed to a 3-inch depth with hardwood mulch at $40 per cubic yard. The area is 240 square feet; at 0.25 ft deep that is 60 cubic feet, which divided by 27 gives 2.22 cubic yards.
The tool shows 2.22 cubic yards, roughly 30 bags if you bought 2-cubic-foot bags, and a bulk cost of about $88.89. Buying 30 bags at even $4 each would run $120, so the bulk yard is clearly the better call for a bed this size.
Tips & common mistakes
- Refresh mulch beds at 2 to 3 inches; going deeper than 4 inches can suffocate roots and cause sour, matted mulch. Reserve 4 to 6 inches only for new gravel driveways or drainage.
- For topsoil that will be seeded, order enough for a settled 4 to 6 inch layer since fresh soil compacts roughly 20 percent after watering.
- Gravel for a walkable base needs a compacted 4-inch minimum; add a separate calculation for the road-base sublayer under decorative stone.
- Round your order up to the nearest half yard for irregular beds and edges, then keep the extra for touch-ups rather than making a second delivery.
- Confirm whether your supplier's yard price includes delivery; a $40 yard can become $55 once a flat delivery fee is spread across a small order.
Mulch, Soil & Gravel Calculator: frequently asked questions
How deep should I set the depth field for mulch versus gravel?
For decorative mulch, enter 2 to 3 inches for a refresh over existing mulch and 3 to 4 inches for a bare bed. For gravel paths or driveways, enter 4 inches for the walking or driving surface, and run the base layer as a separate calculation at another 2 to 4 inches.
Why does the calculator divide by 27?
Landscape suppliers sell by the cubic yard, and one cubic yard equals 27 cubic feet (3 ft x 3 ft x 3 ft). The formula computes your volume in cubic feet first, then divides by 27 so your order matches how the material is actually priced and loaded.
How much area does one cubic yard cover?
One cubic yard covers about 108 square feet at 3 inches deep, 162 square feet at 2 inches, or 81 square feet at 4 inches. The bag estimate assumes 2-cubic-foot bags, so one yard equals roughly 13.5 bags.
Should I order extra to be safe?
Add about 5 to 10 percent for beds with curves, slopes, or uneven grade where depth varies. For a simple rectangular bed measured accurately, the raw number is reliable; excess loose material cannot be returned once it is dumped.
Is bagged or bulk cheaper?
Bulk almost always wins above roughly one cubic yard. The bag count is shown so you can compare: multiply bags by the store's per-bag price and set it against the bulk yard cost plus any delivery fee to see the true break-even.