Gravel Calculator
Calculate how many cubic yards, tons, or bags of gravel you need for any project — driveways, walkways, drainage, or landscaping. Includes bulk vs. bag cost comparison.
Whether you're building a driveway base, filling a drainage trench, or finishing a landscaping bed, this calculator handles the math for you. Select your material below, enter the area dimensions and depth, and you'll instantly see cubic yards, tons, bag counts, and a bulk vs. bag cost comparison. A 10% waste/compaction allowance is included by default — industry standard for most residential projects.
Gravel is the workhorse material of residential construction — it forms the base under driveways and patios, wraps drainage pipe, and finishes off landscaping beds. Ordering the right amount matters because most suppliers charge a delivery fee regardless of load size, and running short mid-project means a second truck, a second fee, and a delay. The calculation itself is straightforward geometry, but the density conversion from volume to weight is where estimates go wrong.
How to calculate gravel yourself
Every gravel estimate starts with three measurements: length, width, and depth. Gravel fills a rectangular volume, so the formula is the same one used for any bulk fill material:
Depth is almost always specified in inches, so divide by 12 before multiplying. For a 50 ft × 12 ft driveway base at 4 inches deep: 50 × 12 × (4 ÷ 12) = 200 cubic feet. Divide by 27 to get cubic yards — the standard unit for bulk aggregate orders — for 7.41 cubic yards. In metric, the same calculation uses metres and centimetres: 15.2 m × 3.7 m × 10 cm = 5.62 m³.
Next, add a waste or compaction allowance. Gravel settles after placement, and loose material is never perfectly efficient to spread, so most estimators add 10% for a standard project. Drainage applications and compacted base layers — where the gravel is deliberately packed down with a plate compactor — should use 15–20%, since compaction alone can reduce loose volume by that much. The driveway example above becomes 7.41 × 1.10 = 8.15 cubic yards after waste.
The final step converts volume to weight, since gravel is sold by the ton for bulk delivery but by the bag (or cubic foot) for small retail purchases. Density varies meaningfully by material — crushed granite is noticeably heavier than pea gravel — so using the correct figure for your chosen material matters.
Types of gravel and their densities
“Gravel” covers a range of materials with different sizes, shapes, and origins, each suited to different jobs. Picking the wrong one can mean a driveway that ruts under vehicle weight or a drainage bed that clogs with fines.
| Material | Density (tons/yd³) | Density (kg/m³) | Common uses |
|---|---|---|---|
| Pea gravel | 1.40 | 1,661 | Paths, landscaping, drainage, playgrounds |
| Crushed stone (limestone) | 1.50 | 1,780 | Driveways, compacted base layers |
| River rock | 1.35 | 1,602 | Landscaping, decorative stream beds |
| Crushed granite | 1.60 | 1,898 | Driveways, high-traffic pathways |
| Sand (dry, as fill) | 1.62 | 1,922 | Paver base, play areas, leveling |
| Lava rock | 1.35 | 1,602 | Decorative landscaping, mulch alternative |
| Slag gravel | 1.45 | 1,721 | Driveways, industrial hardstanding |
Densities above are for dry, loose material. Wet gravel can weigh 5–10% more due to trapped moisture, which matters when calculating delivery weight limits or truck payloads. Angular, crushed materials (crushed stone, crushed granite) interlock and compact more solidly than round materials (pea gravel, river rock), which is why compacted base layers specifically call for crushed stone rather than the rounder decorative types.
When ordering, name the material specifically rather than just saying “gravel.” A supplier’s default stock may be whatever they have the most of that week, which may not suit your application — ask for the material by name and confirm the size grading (e.g., “3/4 inch crushed stone” or “3/8 inch pea gravel”).
Beyond the common materials above, many suppliers also stock a range of decorative and specialty stone — colored landscape rock, polished river stone, or regional stone varieties — priced noticeably higher than standard crushed stone or pea gravel, often $60 to $120 or more per ton. These are typically chosen for visual effect in a landscaping bed or accent area rather than structural performance, so it’s worth reserving the premium spend for the areas where appearance genuinely matters and using standard crushed stone or pea gravel for structural base layers where it will be buried and never seen again.
Drainage-specific gravel deserves its own mention, since it has a different selection criterion than a driveway base. For a French drain or any application where water needs to move freely through the material, “clean” stone — meaning washed gravel with the fine particles and dust removed — is essential. Unwashed crushed stone contains a meaningful fraction of fine material that can clog the voids between larger stones over time, defeating the purpose of a drainage layer. Always specify “clean” or “washed” stone when ordering for a drainage application, and expect to pay a modest premium over unwashed material of the same nominal size.
Gravel depth guide by project type
Depth requirements vary considerably by application, and getting this wrong wastes material in one direction or leaves a structurally inadequate base in the other.
| Project | Recommended depth | Best material | Notes |
|---|---|---|---|
| Driveway base | 4–6 in (10–15 cm) | Crushed stone | Compact in lifts; add a 2 in decorative top layer if desired |
| Walkways & paths | 2–3 in (5–8 cm) | Pea gravel or crushed stone | No compaction equipment usually needed |
| Landscaping beds | 2–3 in (5–8 cm) | River rock, lava rock, or pea gravel | Use landscape fabric underneath to slow weed growth |
| French drain / drainage | 6–12 in (15–30 cm) | Washed drainage stone (3/4 in clean) | Wrap in filter fabric to keep soil from clogging voids |
| Foundation drainage | 12 in (30 cm) or more | Washed crushed stone | Follow an engineered drainage plan for depth and slope |
| Decorative accents | 2 in (5 cm) | River rock, lava rock | Standard for pots, borders, and ground cover |
For any application under a structure or driveway, the gravel must be compacted in lifts rather than dumped and left loose — typically 2–4 inch lifts, each compacted with a plate compactor before the next is added. Skipping this step is one of the most common reasons a driveway base settles unevenly within the first year.
Building a proper driveway base
A gravel driveway is rarely a single layer. Most durable installations use two: a base course of larger, angular crushed stone (3/4 inch to 1.5 inch) for structural strength and drainage, topped with a thinner layer of smaller, more comfortable-to-drive-on material.
Calculate each layer separately using the calculator above — run it once for the 4-inch base course with crushed stone, then again for the 2-inch top course with your chosen surface material (pea gravel and crushed granite are both popular choices). Add the two results together for your total order. This two-pass approach is also useful for any project with layered materials, such as a paver installation with a gravel sub-base and a sand bedding layer on top.
Proper drainage slope matters as much as depth. A driveway should slope at least 1% (roughly 1 inch of drop per 8 feet) away from structures to prevent water pooling, which is the single biggest cause of premature gravel driveway failure — standing water saturates the base and turns it soft under vehicle weight.
Geotextile fabric underneath the base course is worth considering for any driveway built over soft, clay-heavy, or otherwise poor native soil. This woven or non-woven fabric separates the gravel base from the soil beneath it, preventing the two from mixing together over time under repeated vehicle loading — a problem sometimes called “pumping,” where saturated fine soil migrates up into the gravel layer and gradually degrades the base’s load-bearing capacity. Fabric isn’t always necessary on well-draining, sandy, or gravelly native soil, but on clay or consistently wet ground it’s a relatively inexpensive addition (typically $0.15–$0.40 per square foot of material) that can meaningfully extend the life of the driveway base by keeping the two layers properly separated.
Bulk delivery vs. bagged gravel
Like most bulk aggregates, gravel is dramatically cheaper per unit volume when purchased in bulk rather than in retail bags.
A 0.5 cubic foot bag of gravel at a home improvement store costs roughly $4 to $9 depending on material and region. Since one cubic yard equals 27 cubic feet, you need 54 bags to equal a single yard — at $4.50 per bag, that totals about $243 per cubic yard. Bulk delivery, by comparison, typically runs $30 to $60 per ton delivered, or roughly $40 to $90 per cubic yard depending on material density. The gap narrows somewhat compared to sand, but bulk remains meaningfully cheaper for anything beyond a small touch-up job.
Bags remain the practical choice for small jobs — filling gaps around a mailbox post, topping off a flower bed, or a repair patch — where there’s no good place for a delivery truck to dump a pile, or the total need is under a yard. For anything approaching a full driveway, drainage trench, or landscaping bed of any real size, bulk delivery wins decisively on cost, even after accounting for a delivery fee.
Volume-to-weight conversion
Because gravel is priced by the ton for bulk orders, converting your calculated volume to weight is essential for getting an accurate delivered cost, and for making sure a delivery truck or trailer isn’t overloaded.
As quick reference points: one cubic yard of crushed stone weighs about 3,000 lbs (1.5 tons), while a cubic yard of the lighter pea gravel weighs closer to 2,800 lbs (1.4 tons). One cubic foot of crushed stone weighs roughly 110 lbs. A standard dump truck carries 10 to 14 tons per load — for larger orders, your supplier will tell you upfront whether the job needs more than one truck.
For metric users, one cubic metre of crushed stone weighs approximately 1,780 kg (1.78 tonnes). One cubic metre equals 1.308 cubic yards, and one US short ton (2,000 lbs) equals about 0.907 metric tonnes — a roughly 10% difference worth accounting for when comparing quotes across unit systems.
Moisture is the main source of variance between a theoretical calculation and an actual delivered weight. Gravel stored outdoors, especially after rain, can run 5–10% heavier than the bone-dry densities listed above. Reputable suppliers quote and weigh by dry-equivalent tonnage, but it’s reasonable to ask whether their stated density accounts for typical moisture content.
Estimating gravel costs
Pricing varies by material, region, and how you purchase it. The following ranges reflect typical U.S. residential pricing:
| Purchase method | Price range | Cost per yd³ (approx.) | Best for |
|---|---|---|---|
| Bulk delivery (per ton) | $30–$60/ton | $40–$90/yd³ | Projects over 1 yd³ |
| 0.5 ft³ bags (retail) | $4–$9/bag | $216–$486/yd³ | Small repairs, touch-ups |
| Decorative/specialty stone | $60–$120+/ton | Varies widely | Landscaping accents, colored stone |
| Pickup (self-haul, per ton) | $20–$40/ton | $28–$60/yd³ | Small-to-medium loads with a suitable truck |
Self-hauling from a quarry or landscape yard offers the lowest per-ton price but is capped by your vehicle’s payload rating. A full cubic yard of crushed stone weighs around 3,000 lbs, which exceeds most half-ton pickup trucks’ safe payload — check your truck’s door-jamb sticker for the exact rating before loading up, and plan on multiple trips for larger orders rather than overloading a single haul.
Delivery fees typically run $50 to $150 and are commonly waived above a supplier’s minimum tonnage threshold, often 3 to 5 tons. When comparing quotes, calculate the all-in delivered cost per cubic yard, since a lower per-ton price with a high delivery fee can end up costing more than a slightly higher rate with free delivery above your order size.
Common mistakes to avoid
A handful of recurring errors account for most gravel over-orders, under-orders, and installation problems:
Skipping the compaction allowance. A finished, compacted depth of 4 inches typically requires 15–20% more loose material than the theoretical volume, since compaction reduces the air gaps between particles. Ordering only the bare calculated volume for a base layer almost always results in a shortfall once the material is packed down.
Dumping one thick layer instead of compacting in lifts. Gravel bases deeper than 4 inches should go down in stages — spread, compact, then add the next layer — rather than as one loose pile. A single deep, uncompacted layer settles unevenly and creates dips and soft spots within months.
Using the wrong material for a compacted base. Round, decorative materials like river rock and pea gravel don’t lock together the way angular crushed stone does. They look fine as a top-dressing but make a poor structural base under a driveway or patio — the rounded particles shift and roll under load rather than interlocking.
Ignoring drainage slope. Even a correctly sized gravel driveway or path will fail early if water isn’t directed away from it. A minimum 1% grade away from structures prevents the base from becoming saturated and soft.
Ordering “gravel” without specifying size or type. Suppliers stock many grades, and a generic order can arrive as whatever’s currently overstocked rather than what your project needs. Always specify both the material (crushed stone, pea gravel, etc.) and the size grading.
Forgetting the waste factor on odd-shaped areas. Curved paths, irregular beds, and areas with obstacles (posts, drains, existing plantings) waste more material than a clean rectangle. Bump the waste allowance to 15–20% for anything that isn’t a simple rectangular fill.