Mulch & Soil Calculator — Bags vs Bulk
| Bed | Area (sq ft) | Cu ft | Cu yd |
|---|
From "that bed over there" to a number the store understands
Mulch math fails at the units. You measure beds in feet, depth makes the volume three-dimensional, bags are labeled in cubic feet, bulk is sold by the cubic yard, and stone suppliers quote tons. This calculator walks the whole chain: add each bed (rectangles, circles, triangles, or straight square footage), set the depth, and it converts to cubic feet, cubic yards, bag counts and — for gravel and stone — approximate tons. The plan is saved in your browser, which matters for the job you finish "next weekend".
The math, in one pass
- Area: length × width for rectangles, π × (diameter ÷ 2)² for circles, base × height ÷ 2 for triangles. A 10×4 border is 40 sq ft.
- Volume: area × depth in inches ÷ 12. At 3 inches, that border needs 10 cubic feet.
- Yards and bags: divide cubic feet by 27 for cubic yards, or by the bag size for bags — 10 cu ft is 0.37 yd or five 2-cu-ft bags.
- Tons (gravel and stone): cubic yards × typical density. A yard of crushed stone runs about 1.5 tons; pea gravel about 1.4.
Bags or bulk? Let the totals argue it out
A cubic yard equals 13.5 of the common 2-cu-ft bags — so at $4 a bag, a yard of bagged mulch costs $54 before you've loaded a single one into the car. Bulk per-yard prices are usually lower, but the flat delivery fee has to be amortized over the whole order, which is why bags win small jobs and bulk wins big ones. Enter both prices and the calculator shows both totals and the difference; the bag-vs-bulk guide works through where the break-even point usually lands.
Depth is the quiet multiplier
The same bed at 2 inches and 4 inches is a factor-of-two difference in everything downstream — volume, bags, dollars. Pick depth deliberately: 2–3 inches suits most beds, deeper only where coverage or a gravel base genuinely calls for it. Our mulch depth guide maps coverage per bag at each depth, and the raised-bed soil guide and patio-base gravel walkthrough cover the two jobs where depth math surprises people most. One scope note: this tool counts material — how a base should be built or compacted for your specific project is a construction question for local guidance, not a calculator.
Frequently asked questions
How many bags of mulch are in a cubic yard?
A cubic yard is 27 cubic feet, so it equals 13.5 of the common 2 cu ft bags. That one conversion is the key to every bag-vs-bulk price comparison — the calculator does it automatically.
How deep should mulch be?
Two to three inches is the usual range for beds — three if you are after weed suppression. Doubling the depth doubles the volume, so the depth field moves the answer more than people expect.
How do I measure a bed that isn’t a rectangle?
Use the circle or triangle shapes for round and corner beds, or measure an irregular bed roughly and enter its square footage directly with the custom shape. Splitting a curvy bed into two or three simple shapes gets you within a bag.
Is bulk delivery cheaper than bags?
Usually only above a break-even volume, because the delivery fee is flat. Enter your local bag price and bulk price per yard and the tool shows both totals — in many areas the answer flips somewhere around 2 cubic yards.
What about gravel sold by the ton?
Stone and gravel suppliers often quote by weight. The calculator converts your volume to tons using typical densities (pea gravel ≈ 1.4, crushed stone ≈ 1.5 tons per yard) so you can sanity-check a quote. Densities vary by product — confirm with your supplier.
Is my yard plan stored anywhere?
Only in your browser. Beds are saved on your device so the plan is still here next season; nothing is uploaded, and Clear removes it.
Related guides
How Many Bags of Mulch in a Cubic Yard? Bag vs Bulk Math
How many bags of mulch in a cubic yard? 13.5 two-cubic-foot bags — plus the bag-vs-bulk break-even math that decides which one to buy.
How Much Gravel for a Patio Base? Depth and Tonnage Math
Gravel for a patio base, worked step by step: cubic yards for a 10x20 at 4 inches, the 20–25% compaction allowance, and yards-to-tons math.
Mulch Depth Guide: What 2, 3 and 4 Inches Really Cover
Mulch depth math made simple: how far a 2 cu ft bag goes at 2, 3 and 4 inches, which depth fits each job, and the two mistakes that waste bags.
How Much Soil for a 4x8 Raised Bed (and the Cheapest Mix)
How much soil a 4x8 raised bed needs at 6, 10, and 12 inches — exact bag counts, bulk yard math, and a layered fill that cut my cost in half.
Topsoil vs Compost vs Garden Soil: How Much of Each
Topsoil, compost, and garden soil compared: what each bag is for, common blend ratios, and the cubic-foot math for a mixed soil order.