1956
Basalt mulch chart
Put your bed area, basalt mulch depth and waste allowance in: 5200 sq ft at 3 inches with 10% waste needs 5,720.00 sq ft, 52.96 cubic yards exact — order 53 cubic yards.
★ CONSTRUCTION · MULCH · BASALT MULCH CHART
Basalt Mulch Chart: 5200 Sq Ft, 3 Inches, Order 53 Yards
On the defaults — a 5200 square foot bed at 3 inches deep with a 10% waste allowance — you need 5,720.00 square feet of cover, 52.96 cubic yards exact, so order 53 cubic yards. This is the BASALT version — the mulch chart for basalt, a dark volcanic stone that drains well, holds its colour and never breaks down — the sandstone-mulch-chart page is the SANDSTONE version, the granite-mulch-chart page is the GRANITE version, and the mulch-chart page is the GENERAL version for any loose mulch.
What does 52.96 cubic yards of basalt mulch mean?
It means a 5200 square foot bed, once the 10% waste allowance is added, needs 5,720.00 square feet of cover at 3 inches deep — 1,430.00 cubic feet, which is 52.96 cubic yards. Because mulch is sold by the whole yard, you order 53 cubic yards: the extra 0.04 yard covers spillage and the thin spots every bed has. At 3 inches, one cubic yard covers 108.0 square feet, so the same bed at 2 inches would need only 35.31 yards, and at 4 inches it would need 70.62 yards.
Output · formula · meaning
| Output | Formula | What it means |
|---|---|---|
| Area needed | area × (1 + waste ÷ 100) | 5,720.00 sq ft — 5200 × 1.10. |
| Volume in cubic feet | area needed × depth ÷ 12 | 1,430.00 cubic feet — 5,720.00 × 3 ÷ 12. |
| Exact volume | area needed × depth ÷ 324 | 52.96 cubic yards — 5,720.00 × 3 ÷ 324. |
| Order quantity | round exact volume up to a whole yard | 53 cubic yards — the next whole yard above 52.96. |
| Coverage per yard | 324 ÷ depth | 108.0 sq ft per yard — 324 ÷ 3. |
| Area behind a target volume | target volume × 324 ÷ depth ÷ (1 + waste ÷ 100) | 5200 sq ft — 52.96 × 324 ÷ 3 ÷ 1.10, rounded. |
| Depth behind a target volume | area needed × depth ÷ 324, solved for depth | 3 inches — the depth that turns 5,720.00 sq ft into 52.96 yards. |
| Waste behind a target volume | target volume × 324 ÷ depth ÷ area − 1, as a percent | 10% — the allowance that turns 5200 sq ft into 5,720.00 sq ft. |
Three things to check before you trust the number
First, measure the bed honestly: length times width for each bed, added together, with L-shaped beds split into rectangles. A guessed area moves the order by the same percentage as the guess. Second, keep the depth honest: basalt does not break down, so the layer you spread is the layer that stays — but the stones scatter onto paths and lawns when raked or walked on, so edge the bed if you want the depth to hold. Third, do not skip the waste allowance on basalt: the stones are angular and lock together, so they stay put better than round gravel on slopes, but spillage at the edges and uneven ground still eat into the load, so the 10% allowance is the difference between finishing the bed and running short with the truck already gone.
Worked example
Area 5200 sq ft, depth 3 inches, waste 10%. Area needed: 5200 × 1.10 = 5,720.00 sq ft. Exact volume: 5,720.00 × 3 ÷ 324 = 52.96 cubic yards. Order: round 52.96 up to 53 cubic yards. Drop the waste to 0% and the exact volume falls to 48.15 yards, order 49; drop the depth to 2 inches and it falls to 35.31 yards, order 36. Depth moves the answer faster than waste does, because every inch adds a full layer across the whole bed.
Basalt mulch lookup table
Every row below applies 10% waste to the area first, then divides by 324: yards = area needed × depth ÷ 324, rounded up to the next whole yard for the order. Find your bed size and depth, read across, and order the last column.
| Area (sq ft) | Depth (inches) | Area needed (sq ft, 10% waste) | Exact (cubic yards) | Order |
|---|---|---|---|---|
| 250 | 2 | 275.00 | 1.70 | 2 cubic yards |
| 250 | 3 | 275.00 | 2.55 | 3 cubic yards |
| 500 | 2 | 550.00 | 3.40 | 4 cubic yards |
| 500 | 3 | 550.00 | 5.09 | 6 cubic yards |
| 750 | 3 | 825.00 | 7.64 | 8 cubic yards |
| 750 | 4 | 825.00 | 10.19 | 11 cubic yards |
| 1000 | 2 | 1,100.00 | 6.79 | 7 cubic yards |
| 1000 | 3 | 1,100.00 | 10.19 | 11 cubic yards |
| 1200 | 2 | 1,320.00 | 8.15 | 9 cubic yards |
| 1400 | 3 | 1,540.00 | 14.26 | 15 cubic yards |
| 1500 | 3 | 1,650.00 | 15.28 | 16 cubic yards |
| 1500 | 4 | 1,650.00 | 20.37 | 21 cubic yards |
| 1750 | 2 | 1,925.00 | 11.88 | 12 cubic yards |
| 2000 | 3 | 2,200.00 | 20.37 | 21 cubic yards |
| 2500 | 3 | 2,750.00 | 25.46 | 26 cubic yards |
| 3000 | 2 | 3,300.00 | 20.37 | 21 cubic yards |
Every branch, checked
A 5200 square foot bed at 3-inch depth with 0% waste gives 48.15 cubic yards exact, order 49 cubic yards. The same bed at 2-inch depth with 10% waste gives 35.31 cubic yards exact, order 36 cubic yards. A 4950 square foot bed at 3-inch depth with 10% waste gives 50.42 cubic yards exact, order 51 cubic yards. A 5450 square foot bed at 3-inch depth with 10% waste gives 55.51 cubic yards exact, order 56 cubic yards. Each branch changes exactly one input, so the difference from 52.96 isolates that input.
The reverses, worked backwards
The area behind 52.96 cubic yards is 5200 sq ft: at 4950 sq ft the figures are 50.42 cubic yards exact, order 51 cubic yards, and at 5450 sq ft they are 55.51 cubic yards exact, order 56 cubic yards. The depth behind 52.96 cubic yards is 3 inches: at 2 inches the figures are 35.31 cubic yards exact, order 36 cubic yards, and at 4 inches they are 70.62 cubic yards exact, order 71 cubic yards — one inch either way moves the order by about 17.0 yards. The waste behind 52.96 cubic yards is 10%: at 5% the figures are 50.56 cubic yards exact, order 51 cubic yards, and at 15% they are 55.37 cubic yards exact, order 56 cubic yards — waste moves the exact volume, and at 15% it lifts the order to 56 yards.
What the defaults assume
The defaults assume a flat 5200 square foot bed, a uniform 3-inch layer, and a 10% waste allowance. Real basalt beds are rarely flat: slopes shed stones downhill, paths and tree trunks eat into the area, and loose stones wander into the lawn, so measure the planted area only and keep the waste allowance on sloped ground. Zero square feet is the honest edge: 0.00 cubic yards exact, order 0. A depth of zero or below, a negative area, or a negative waste allowance is rejected, because none of them describes a real bed.
Who uses this
A gardener dressing beds with basalt: the 5200 square foot headline is a large garden bed, and the table covers everything from a 250 square foot border to a 3000 square foot yard. A landscaper quoting a basalt job: the waste column protects the quote, and the order column is the number given to the supplier. A homesteader spreading bulk basalt on paths: the 3-inch rows are the bed depths, and the 2-inch rows are the path depths. A community garden coordinator splitting a bulk delivery: each plot reads its own row, and the orders add up to the truckload.
Accuracy & limitations
The arithmetic is exact for the inputs entered; the judgement is in the inputs. A guessed area, a depth measured before the stones scatter, or a skipped waste allowance will each move the answer by exactly the amount of the error, every load. The model does not include stones scattering into lawns, delivery minimums, or compaction — a supplier may sell only in whole yards or charge extra below a minimum, so confirm the order quantity with the supplier. This page is a calculation tool, not landscaping advice.
Cite this calculator
Basalt mulch 5200 sq ft at 3-inch depth with 10% waste needs 5,720.00 sq ft, 52.96 cubic yards exact, order 53 yards. Free calculator, plus 16-row table. Source: Bright Side Kit, https://brightoolbox.com/basalt-mulch-chart/, accessed 31 October 2026 (2026-10-31).
Frequently asked questions
Why does the table apply waste to the area first?
Because waste is lost cover: spillage, scattering and uneven ground mean you need more covered area than the bed measures. Adding 10% to the area, then converting to yards, keeps the waste in the same units as the bed. Applying it after the conversion gives the same number here, but the area-first order keeps the table readable.
How deep should basalt mulch really be?
Three inches is the standard bed layer on this page, and 2 inches suit paths and top-ups. Basalt does not break down, so a 3-inch spread stays 3 inches; if stones scatter, rake them back or top up the thin spots.
Does basalt mulch introduce weed seeds?
Basalt is mineral, so it carries no weed seeds at all; weeds can still root in the dust and debris that collects on top of it, so use fabric underneath and clear the debris. This calculator prices volume only and does not judge the gardening choice.
What if my bed is not a rectangle?
Split it into rectangles, measure each, and add the areas before entering the total. A circle uses radius times radius times 3.14. Guessing one number for an irregular bed is the most common reason orders come up short.
Why order 53 yards when the exact figure is 52.96?
Because mulch is sold by the whole yard and you cannot buy 0.04 of a yard from most suppliers. Rounding up also covers spillage and thin spots; the 0.04 yard of headroom is cheaper than a second delivery for a shortfall.
Can I use this chart for other mulch types?
The volume math is the same for any loose mulch — area, depth and waste convert the same way — but settling and coverage differ by material. Basalt does not settle like bark, so use the basalt rows for basalt and the matching chart for bark or wood chips.