Gravel Calculator
This gravel calculator estimates how much gravel you need in cubic feet, cubic yards, pounds, and tons from the same measurements contractors use on site. Enter the project length and width in feet, depth in inches, the gravel density in pounds per cubic foot, and any waste allowance you want to carry for uneven ground, spillage, or compaction. The result helps when a supplier sells by the yard but a hauler quotes by the ton, or when you want a quick check before ordering stone for a driveway, path, drainage trench, or landscape bed. Gravel orders go wrong most often when depth is guessed instead of measured, or when people convert area to weight without accounting for density. This page keeps those steps in one place. It first finds the raw volume, then applies any waste percentage, then converts the adjusted volume into weight using the density you entered. If you do not have a supplier spec sheet yet, a common planning estimate is around 95 to 110 lb per cubic foot depending on gravel type, shape, and moisture.
Quick answer
The calculator starts with volume, because gravel fills space before it creates weight.
What this tells you
- •The calculator starts with volume, because gravel fills space before it creates weight.
- •Depth is entered in inches and converted to feet so the length, width, and depth units match.
- •Waste allowance increases the raw volume before weight is calculated, which helps cover uneven subgrade, settling, and minor overrun.
- •Density changes the tonnage a lot, so the same cubic yard count can produce different weight estimates for pea gravel, crushed stone, or wet material.
- •The tool returns both pre-waste volume and with-waste totals so you can compare a neat geometric estimate with the amount you may actually order.
How to Use
- 1Measure the length and width of the area in feet. Break irregular spaces into rectangles, calculate each rectangle, and add the totals before ordering.
- 2Enter the target depth in inches. Use compacted depth if you know the finished thickness you want after the gravel is spread and settled.
- 3Enter density in lb/ft3 if your supplier provides it. If not, use a reasonable planning estimate such as 100 or 105 lb/ft3 and confirm before purchase.
- 4Add an optional waste allowance if the job has sloped edges, soft spots, or material loss during hauling and spreading. Many small residential orders use 5% to 10%.
- 5Calculate the result, then review cubic yards and tons together. Order in the unit your yard or quarry uses, and round up to the supplier's delivery increment if needed.
How It Works
Formula
Depth(ft) = Depth(in) / 12
Cubic Feet = Length x Width x Depth(ft)
Cubic Yards = Cubic Feet / 27
Waste Multiplier = 1 + Waste% / 100
Adjusted Cubic Feet = Cubic Feet x Waste Multiplier
Weight(lb) = Adjusted Cubic Feet x Density
Weight(tons) = Weight(lb) / 2000The gravel formula in `lib/formulas/gravel-calculator.ts` uses a simple volume-to-weight flow. First it converts depth from inches to feet so all dimensions are compatible. Next it multiplies length, width, and depth to get cubic feet, then divides by 27 to get cubic yards. After that it applies the waste multiplier to the volume, not to the final tonnage separately, which keeps the math consistent. Finally it multiplies adjusted cubic feet by density in pounds per cubic foot and divides by 2,000 to estimate short tons. In plain language, the tool answers two questions in order: how much space the gravel must fill, and how much that volume should weigh for the material you chose.
Calculation note: values are processed in the order shown above, using the current input units.
Worked Examples
Driveway gravel estimate
A 4 inch layer is 0.3333 feet deep. Multiply 20 x 10 x 0.3333 to get 66.67 cubic feet, then divide by 27 for 2.47 cubic yards. Adding 10% waste gives 73.33 cubic feet or 2.72 cubic yards. At 105 lb per cubic foot, that adjusted volume weighs 7,700 lb, which is 3.85 tons.
Patio base under pavers
Three inches converts to 0.25 feet. The raw volume is 12 x 16 x 0.25 = 48 cubic feet, which is 1.78 cubic yards. With a 5% waste factor, the total rises to 50.40 cubic feet. At 100 lb per cubic foot, the estimated order weight is 5,040 lb or 2.52 tons.
Garden path top-up
A 2 inch refresh layer equals 0.1667 feet. Multiply 30 x 4 x 0.1667 and the path needs 20 cubic feet before waste, or 0.74 cubic yard. After adding 8% for uneven spread and touch-up, the order becomes 21.60 cubic feet. Using a lighter 95 lb per cubic foot density produces 2,052 lb, which is about 1.03 tons.
Drainage trench fill
Eight inches is 0.6667 feet. The trench volume is 40 x 1.5 x 0.6667 = 40 cubic feet, and 40 divided by 27 is 1.48 cubic yards. With 12% waste, the adjusted quantity is 44.80 cubic feet or 1.66 cubic yards. Multiplying by 110 lb per cubic foot gives 4,928 lb, which rounds to 2.46 tons.
Play area pea gravel bed
Five inches equals 0.4167 feet of depth. The raw bed volume is 18 x 14 x 0.4167 = 105 cubic feet, which converts to 3.89 cubic yards. After a 7% allowance, the total becomes 112.35 cubic feet or 4.16 cubic yards. At 100 lb per cubic foot, the material weight is 11,235 lb, or 5.62 tons.
Gravel Coverage Per Ton
Approximate area one ton of gravel covers at common depths, assuming a typical density of 105 lb per cubic foot.
| Depth | Coverage per ton | Tons per 100 sq ft |
|---|---|---|
| 2 inches | about 110 sq ft | 0.9 tons |
| 3 inches | about 75 sq ft | 1.3 tons |
| 4 inches | about 55 sq ft | 1.8 tons |
| 6 inches | about 38 sq ft | 2.7 tons |
Coverage changes with density and compaction. Heavier or wetter stone covers less area per ton than lighter dry gravel.
Why yards and tons both matter
Many homeowners sketch a gravel project in square feet, then run into a supplier who sells in cubic yards and a hauler who quotes by the ton. That mismatch is normal. Volume tells you how much space the stone will fill. Weight tells you how much that filled space should weigh once you pick a material density. A useful order check is to compare both numbers before calling in the load.
A cubic yard is always 27 cubic feet, but the weight of that yard changes with the stone. At 105 lb per cubic foot, one cubic yard weighs 27 x 105 = 2,835 lb, or about 1.42 tons. If the gravel is closer to 95 lb per cubic foot, that same yard is about 1.28 tons. If it is 110 lb per cubic foot, the yard is about 1.49 tons. That is why a single yards-to-tons rule only works as a rough estimate.
Depth is the other number that changes the order quickly. A 100 square foot area at 2 inches deep needs only about 16.67 cubic feet before waste. The same area at 6 inches deep needs 50 cubic feet, which is exactly three times more material. Before you increase the project footprint, make sure the target depth matches the job, especially for driveways, trench stone, and paver base layers.
If you are planning a layered build, calculate each layer separately instead of averaging the densities together. For example, a driveway may use one depth for larger base rock and another for top gravel. Running each layer on its own gives a cleaner purchase list and makes supplier conversations easier.
Common mistakes
- Entering depth in inches mentally but typing it as feet. A 4 inch layer is 0.3333 foot, not 4 feet, so a unit slip can multiply the order by 12.
- Using area alone to guess tons. Two projects with the same square footage can need very different tonnage if one is 2 inches deep and the other is 6 inches deep.
- Keeping the default density when the supplier's material is heavier or lighter. Density is the step that turns cubic feet into pounds, so it deserves a quick check.
- Skipping waste on jobs with irregular edges, drainage shaping, or soft subgrade. The neat rectangle math may be right while the delivered quantity still comes up short.
- Rounding down too early. Keep the calculator result through the end, then round according to the supplier's minimum order size or truck capacity.
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