What is gravel?
Gravel is loose granular stone. In everyday landscaping and building conversations, the name can also refer to crushed rock products. A supplier’s product name alone does not tell you its exact size, grading or suitability for a particular job.
Before calculating an order, separate two questions: which material does your project need, and how much space will it fill? An accurate quantity cannot make an unsuitable material work.
Not all gravel is the same
Crushed stone has angular pieces; naturally rounded gravel has smoother edges. Size, the mixture of particle sizes and the amount of fine material also matter. Ask for the product specification rather than choosing by color alone.
Crushed stone
Rounded gravel
Match the material to the job
- Driveways and compacted bases: confirm the specified aggregate, layer thickness and compaction requirements. Decorative rounded stone is not automatically a substitute for base material.
- Paths and decorative beds: consider how the surface will feel underfoot, how it will be contained and whether it needs to support wheels or furniture.
- Drainage: use the material and grading required by the drainage design. Do not assume every product sold as gravel drains equally well.
The calculator includes crushed stone, pea gravel, river rock, limestone, granite and a custom-density option. These are quantity-estimating choices, not approval of a material for your site.
A quantity estimate is not a driveway, foundation or drainage design. Confirm required depths and materials with your plans, installer or supplier.
Start with length, width and depth
Measure the footprint you intend to cover. The depth is the thickness of the gravel layer you are adding—not necessarily the depth of the hole. Keep the units beside every measurement.
- Rectangle: record length and width. For a circular area, record the diameter, not the radius.
- Irregular area: divide it into simple sections and add their areas. Avoid counting overlapping sections twice.
- Different depths: calculate each section separately, then combine the required volumes before arranging an order.
- Known area or volume: use the calculator’s corresponding input mode instead of inventing dimensions.
If your plan specifies a compacted thickness, ask how that relates to delivered loose material. There is no universal allowance that fits every aggregate and site.
How to calculate gravel volume
For a rectangle, volume equals length × width × depth. Convert all three dimensions to the same unit first. Feet produce cubic feet; meters produce cubic meters.
With length and width in feet and depth in inches: cubic yards = length × width × depth ÷ 324. The divisor combines 12 inches per foot and 27 cubic feet per cubic yard.
Worked example: 20 ft × 15 ft × 4 in
- Area: 20 × 15
- 300 ft²
- Depth: 4 ÷ 12
- ⅓ ft
- Volume: 300 × ⅓
- 100 ft³
- Cubic yards: 100 ÷ 27
- ≈ 3.70 yd³
- Extra allowance
- 0%
- Suggested bulk order
- 3.8 yd³
The calculator rounds the adjusted bulk volume upward to the next 0.1 yd³. The underlying volume here is about 3.7037 yd³, not exactly 3.70. The 3.8 yd³ suggestion is purchasing rounding, not an added compaction factor.
When you enter an allowance, it is applied once: measured volume × (1 + allowance ÷ 100). For this example, 10% gives about 4.0741 yd³ and a suggested order of 4.1 yd³. Neither percentage is a recommendation for your project.
Should you order yards, tons or bags?
Cubic yards and cubic meters measure volume. A ton measures weight. To convert volume to weight, you need a density expressed in compatible units. One US short ton is 2,000 lb; a metric tonne is 1,000 kg. Confirm which unit the quote uses.
Understanding the weight estimate
The calculator uses planning densities. At its crushed-stone assumption of 1.4 US short tons per cubic yard, the example’s 3.7037 yd³ is approximately 5.19 short tons. Weight is based on the allowance-adjusted requirement, not the rounded 3.8 yd³ order. Supplier density and moisture can change the actual load weight.
Buying gravel in bags
Use the volume printed on the package. For the example’s 100 ft³ requirement, 0.5 ft³ bags mean 100 ÷ 0.5 = 200 whole bags with no allowance. Bag counts round up independently from the bulk-order suggestion. If a bag lists weight only, ask for its volume or a suitable product-specific conversion.
Compare the complete quote
- Compare the same material and required quantity, not simply the price of one bag against one ton.
- Include delivery charges, minimum orders and the supplier’s order increments.
- Check vehicle access, unloading space and how you will move the material to its final location.
- Confirm whether the quote includes taxes or other services. The calculator does not automatically add unentered charges or installation labor.
In Advanced options, you can enter bulk pricing, bag volume and price, delivery cost and truck capacity. If both bulk and bag prices are entered, the calculator uses bulk pricing; it does not automatically select the cheapest purchasing method.
Common estimating mistakes
- Mixing feet and inches: a 4-inch depth is one-third of a foot, not 4 feet.
- Using rounded intermediate numbers: keep full precision until the final order is rounded.
- Confusing tons and yards: weight requires density; there is no single conversion for every gravel product.
- Adding the allowance twice: check whether your supplied volume already contains an allowance.
- Treating a default depth as a specification: replace example measurements with values appropriate to your project.
Questions before you order
How much area does a cubic yard cover?
Divide 27 ft³ by the layer depth in feet. At an illustrative 3-inch depth, one cubic yard covers 108 ft² before allowance. This describes volume coverage, not a recommended installation depth.
How many bags of gravel equal a cubic yard?
One cubic yard contains 27 ft³. Divide 27 by the volume printed on each bag: 0.5 ft³ bags require 54 bags, while 1 ft³ bags require 27 bags. These quantities contain no extra allowance. For other bag sizes, round up to a whole bag. A bag’s weight alone does not establish its volume; check the product label or supplier. Use the Gravel Calculator for your project quantity.
Can I calculate a circular gravel bed?
Yes. Select Circle and enter its diameter and planned depth. The area is π × radius², where radius is half the diameter. Exclude any area that will not receive gravel.
Does the estimate include compaction?
There is no hidden site-specific compaction calculation. An entered allowance increases the quantity once. Ask your supplier or installer what loose quantity is needed for your specified finished layer.
Can I use this for a paver base?
You can estimate a specified gravel layer’s volume here. For paver counts and separate base and bedding-sand estimates, use the Paver Calculator. Neither tool chooses the structural design for you.
Sources and limitations
This guide explains material planning and the behavior of our calculator. It does not replace product specifications, local requirements or professional design advice.
- USGS: crushed stone — background on crushed stone as a construction raw material.
- Strata: gravel glossary — terminology and common uses. Product suitability still needs project-specific confirmation.
- DailyUseCalc calculation methodology — unit conversion, allowance and ordering behavior used in the examples.
Examples are illustrative, not supplier quotations. Confirm material density, package coverage, delivery limits and final order quantities before buying.