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Coral chip chart calculator
Put your area, depth and waste allowance in: 850 sq ft at 3 inches with 10% waste needs 935.00 sq ft, 8.66 cubic yards exact, order 9 cubic yards.
★ CONSTRUCTION · LANDSCAPING · CORAL
Coral Chip Chart: 850 Sq Ft, 3 Inches, Order 9 Yards
On the defaults — 850 square feet of coral chips at 3 inches deep with a 10% waste allowance — you need 935.00 square feet of cover, which is 8.66 cubic yards exact, so order 9 cubic yards. This is the CORAL chart — smooth coral chips for beds, paths and borders priced by the yard — the porcelain-chip-chart page is the PORCELAIN version — smooth porcelain chips for beds, paths and borders priced the same way; the river-rock-chip-chart page is the RIVER ROCK version — smooth rounded stone chips for beds and borders priced the same way; the crushed-stone-chip-chart page is the CRUSHED STONE version — plain crushed stone chips for beds, paths and borders priced the same way; and the red-rock-chip-chart page is the RED ROCK version — warm red stone chips for beds and borders priced the same way.
What does 8.66 cubic yards of coral chips mean?
It means that 850 square feet at 3 inches deep, plus a 10% waste allowance, is 935.00 square feet of cover, which is 8.66 cubic yards of coral chips — so the order is 11 cubic yards, because suppliers sell whole yards. The two numbers are the whole story in miniature: the exact figure is what the bed truly holds, and the order is the exact figure rounded up, because a short delivery leaves part of the bed thin. The part people get wrong is ordering the exact figure: 8.66 yards ordered as 10 leaves the last stretch short, and a second delivery costs more than the spare yard. The other part people get wrong is the reverse — skipping the waste allowance, which understates the order by almost a full yard on a bed this size.
Three things to check before you trust the number
Is 850 square feet really the bed, or the whole garden? Eight hundred square feet is the bed’s area, and it is the figure the needed area turns on: the 1100-square-foot branch totals 11.20 cubic yards exact, order 12, against the 8.66 headline, so a 250-square-foot overstatement is about 2.5 yards. If the 850 counts paths already covered or lawn that needs no chips, the order is overstated by roughly a yard per 100 square feet at this depth — measure the bed alone.
Is 3 inches really the depth, or the depth on delivery day? Four inches is the finished depth, and it is the figure the exact yards turn on: the 2-inch branch totals 5.43 cubic yards exact, order 6, against the 8.66 headline, so one inch of depth is about 3 yards on this bed. Coral chips settle and wash thin, so a bed filled to 2 inches ends nearer 1.5 within a season — measure the finished depth you want, not the depth on delivery day.
Is 10% waste enough for your ground? Ten percent is the waste allowance, and it is the figure the needed area turns on: the 0%-waste branch totals 9.88 cubic yards exact, order 10, against the 8.66 headline, so the allowance itself is about 0.8 yards. On sloped or un-edged beds, spillage and drift run past 10% — raise the allowance rather than ordering short.
Worked example
On the defaults: 850 square feet, 3 inches deep, 10% waste allowance.
- Needed area: 850 × 1.10 is 935.00 sq ft.
- Coverage per cubic yard: 324 ÷ 3 is 108 sq ft.
- Exact cubic yards: 935.00 × 3 ÷ 324 is 8.66.
- Order: 8.66 rounded up is 11 cubic yards — the exact figure rounded up, because suppliers sell whole yards.
And the other way: the area behind 8.66 cubic yards is 850 sq ft, the depth behind 8.66 cubic yards is 3 inches, and the waste behind 8.66 cubic yards is 10%. With 0 square feet the model honestly shows 0.00 cubic yards — an empty bed needs no coral chips.
Coral chip lookup table
Every row below is the same formula at 10% waste: needed area is area × 1.10, exact cubic yards are needed area × 3 ÷ 324, and the order is the exact figure rounded up. Find your area row, or use the calculator above for any size the table does not list.
| Area (sq ft) | Depth (inches) | Needed area (sq ft) | Exact cubic yards | Order |
|---|---|---|---|---|
| 100 | 3 | 110.00 | 1.02 | 2 cubic yards |
| 150 | 3 | 165.00 | 1.53 | 2 cubic yards |
| 200 | 3 | 220.00 | 2.04 | 3 cubic yards |
| 250 | 3 | 275.00 | 2.55 | 3 cubic yards |
| 300 | 3 | 330.00 | 3.06 | 4 cubic yards |
| 400 | 3 | 440.00 | 4.07 | 5 cubic yards |
| 500 | 3 | 550.00 | 5.09 | 6 cubic yards |
| 600 | 3 | 660.00 | 6.11 | 7 cubic yards |
| 700 | 3 | 770.00 | 7.13 | 8 cubic yards |
| 800 | 3 | 880.00 | 8.15 | 9 cubic yards |
| 900 | 3 | 990.00 | 9.17 | 10 cubic yards |
| 1000 | 3 | 1,100.00 | 10.19 | 11 cubic yards |
| 1200 | 3 | 1,320.00 | 12.22 | 13 cubic yards |
| 1500 | 3 | 1,650.00 | 15.28 | 16 cubic yards |
| 1800 | 3 | 1,980.00 | 18.33 | 19 cubic yards |
| 2000 | 3 | 2,200.00 | 20.37 | 21 cubic yards |
Every branch, checked
- 850 square feet, 3-inch depth, 0% waste: 850 square feet, 3-inch depth, 0% waste: 7.87 cubic yards exact — order 8 cubic yards.
- 850 square feet, 2-inch depth, 10% waste: 850 square feet, 2-inch depth, 10% waste: 5.77 cubic yards exact — order 6 cubic yards.
- 1100 square feet, 3-inch depth, 10% waste: 1100 square feet, 3-inch depth, 10% waste: 11.20 cubic yards exact — order 12 cubic yards.
- 500 square feet, 3-inch depth, 10% waste: 500 square feet, 3-inch depth, 10% waste: 5.09 cubic yards exact — order 6 cubic yards.
The reverses, worked backwards
- Area behind 8.66 cubic yards: 850 sq ft — at 850 sq ft the figures are 8.66 cubic yards exact — order 9 cubic yards.; at the lower neighbor the figures are 8.15 cubic yards exact — order 9 cubic yards.; at the upper neighbor the figures are 9.17 cubic yards exact — order 10 cubic yards...
- Depth behind 8.66 cubic yards: 3 inches — at 3 inches the figures are 8.66 cubic yards exact — order 9 cubic yards.; at the lower neighbor the figures are 7.21 cubic yards exact — order 8 cubic yards.; at the upper neighbor the figures are 10.10 cubic yards exact — order 11 cubic yards...
- Waste behind 8.66 cubic yards: 10% waste — at 10% waste the figures are 8.66 cubic yards exact — order 9 cubic yards.; at the lower neighbor the figures are 8.26 cubic yards exact — order 9 cubic yards.; at the upper neighbor the figures are 9.05 cubic yards exact — order 10 cubic yards...
What the defaults assume
The defaults are 850 square feet of coral chips at 3 inches deep with a 10% waste allowance, so the headline is one garden bed, one delivery, one depth. The model is a multiplication and a division: the needed area is area times one plus waste over one hundred, and the exact yards are needed area times depth divided by 324 — because one cubic yard at one inch deep covers 324 square feet. The area reverse is checked at 50 square feet either side, because 50 square feet at 3 inches with 10% waste is 0.51 yards; the depth reverse is checked at half an inch either side, because half an inch over 935 square feet is 1.44 yards; the waste reverse is checked at 5% either side, because 5% of 850 square feet at 3 inches is 0.39 yards. The model does not include edging, landscape fabric, or delivery charges — price those separately, and re-check the order when the bed or the depth changes.
Output · formula · meaning
| Output | Formula | What it means |
|---|---|---|
| Needed area | area × (1 + waste ÷ 100) | 935.00 sq ft — 850 × 1.10. |
| Coverage per cubic yard | 324 ÷ depth in inches | 108 sq ft — 324 ÷ 3. |
| Exact cubic yards | needed area × depth ÷ 324 | 8.66 — 935.00 × 3 ÷ 324. |
| Order | exact cubic yards, rounded up | 11 cubic yards — 8.66 rounded up. |
| 850 square feet, 3-inch depth, 0% waste | same model | 7.87 cubic yards exact — order 8 cubic yards. |
| 850 square feet, 2-inch depth, 10% waste | same model | 5.77 cubic yards exact — order 6 cubic yards. |
| 1100 square feet, 3-inch depth, 10% waste | same model | 11.20 cubic yards exact — order 12 cubic yards. |
| 500 square feet, 3-inch depth, 10% waste | same model | 5.09 cubic yards exact — order 6 cubic yards. |
| Area behind 8.66 cubic yards | reverse | 850 sq ft: 8.66 cubic yards exact — order 9 cubic yards. |
| Depth behind 8.66 cubic yards | reverse | 3 inches: 8.66 cubic yards exact — order 9 cubic yards. |
| Waste behind 8.66 cubic yards | reverse | 10% waste: 8.66 cubic yards exact — order 9 cubic yards. |
| 0 square feet | same model | 0.00 cubic yards exact — order 0 cubic yards. |
| Negative area | same model | Area — 0 or more. |
| Zero depth | same model | Depth — more than 0. |
| Negative waste | same model | Waste allowance — 0 or more. |
| 324 square feet, 0% waste | same model | 3.00 cubic yards exact — order 3 cubic yards. |
Who uses this
- A homeowner ordering coral chips for a garden bed — 850 sq ft at 3 inches is 8.66 yards exact, order 11, with the table covering other bed sizes before the delivery is booked.
- A landscaper quoting a coral job — the branches price 0% waste or a shallower depth at once, so a quote can show the client the exact-versus-order gap.
- A gardener comparing coral chips with stone — the same formula drives the river-rock, crushed-stone and pea-gravel charts, so materials can be compared yard for yard.
- A DIYer working out whether a bulk delivery beats bags — the exact figure against bag coverage shows how many bags a bulk order replaces.
Accuracy & limitations
Figures are the model’s own arithmetic on the numbers you type, computed from unrounded values and displayed rounded HALF_UP to 2dp. The main limitation is the inputs, not the arithmetic: whether the area is the bed alone, whether the depth is the finished depth after settling, and whether the waste allowance fits the ground are all judgement calls, and this page prices the figures you enter without checking them. Coral chips vary in size and pack differently by source, so treat the order as a planning figure and confirm with your supplier. This page is a calculation tool, not landscaping advice.
Cite this calculator
850 sq ft of coral chips at 3 inches with 10% waste: 935.00 sq ft, 8.66 cubic yards exact, order 9 cubic yards. Source: Bright Side Kit, https://brightoolbox.com/coral-chip-chart/, accessed 29 October 2026.
Frequently asked questions
Why divide by 324?
One cubic yard is 27 cubic feet, and one inch of depth over one square foot is 1/12 cubic foot; 27 ÷ (1/12) = 324 square feet at one inch deep. At 3 inches the same yard covers 108 square feet, which is why depth divides the coverage.
Why order 11 yards when the exact figure is 8.66?
Suppliers sell whole cubic yards, and a short bed is worse than a spare pile: the extra 0.34 yards covers spillage, thin spots and settling, and stores well for top-ups.
Does the waste allowance change with the depth?
No: waste is a percentage of area, applied before the depth multiplication. A 10% allowance on 850 square feet is 935.00 square feet at any depth; deeper beds just need more yards for the same allowance.
What if my bed is not a rectangle?
Split it into rectangles and triangles, add the areas, and enter the total. A circle’s area is 3.14 times its radius squared; an L-shape is two rectangles added together.
Do coral chips need a different depth than stone?
The formula is identical for any loose fill; only the finished look differs. Coral chips are light and drift more than stone, so edging matters more, but the yardage math is the same.
How many bags is 9 cubic yards?
A 2-cubic-foot bag is 1/13.5 of a yard, so 9 yards is about 122 bags — which is why bulk delivery beats bags for any bed this size.