Gravel Calculator
Find out how many cubic yards and tons of gravel you need for a path, base, or driveway.
Area dimensions
Results
For a 20 ft × 3 ft area at 3 in deep, you'll need about 0.78 tons of gravel (roughly 0.56 cubic yards).
Gravel needed
0.78 tons
That's a small amount — typical for a short garden path or small patch.
Many suppliers have a minimum order size around 1 ton for delivery — call ahead to confirm, since a sub-minimum order may cost the same as ordering up to the minimum.
Area covered: 60 sq ft
Volume: 0.56 cubic yards
How this works
Area (length × width) is multiplied by your target depth to get a raw volume in cubic feet, converted to cubic yards (the standard bulk-aggregate purchase unit), and multiplied by your material's density (tons per cubic yard) to get the tonnage most suppliers actually price and deliver by. Depth and density are both user-adjustable since they vary meaningfully by project type (path versus driveway) and material (crushed stone versus pea gravel versus river rock) — the defaults reflect typical values for a general-purpose crushed-stone path, not any specific product. This calculator's flat-area model assumes a single rectangular area and a single material layer; for two-layer systems (a coarser base plus a decorative top layer) or irregular, sloped, or curved areas, see the FAQ and edge-case guidance above for how to adapt the calculation. Depth is deliberately kept as a single flat figure rather than a range, because averaging several site measurements (as recommended in the FAQ) is simpler for most users than entering a min/max and having the tool compute a weighted result — the tradeoff is that a very uneven site needs manual pre-averaging before the number goes in. Density is treated the same way: rather than trying to look up every possible gravel product's exact tested density internally, the calculator exposes it as a single adjustable field with a bounded realistic range (roughly 1.1 to 1.9 tons per cubic yard), so the result stays accurate as long as you can find your specific product's number on a supplier spec sheet — if you can't, the 1.4 ton/cubic yard default is a reasonable general-purpose crushed-stone estimate, not a guess pulled from nowhere. If your project genuinely doesn't fit a single rectangular area and single flat depth — a curved path, a two-layer base system, a site with a retaining wall — the recommended approach throughout this page is the same one used by professional estimators: break the job into simpler sub-areas, run the calculation once per sub-area, and sum the results, rather than trying to force one calculation to capture a complex shape. The unit toggle switches every input and result between imperial (feet, cubic yards, tons) and metric (metres, cubic metres) — internally, every calculation always runs in the same canonical units regardless of which one you're viewing, so switching back and forth never introduces rounding drift into your entered values. Gravel density default (~1.4 tons/cubic yard): Braen Stone, "Calculating How Much Stone You Need".
Worked example
A garden path 20 ft × 3 ft, filled with crushed stone at the default 3-inch depth and default 1.4 tons/cubic yard density: area is 60 sq ft, and at 3 inches (0.25 ft) deep, that's 60 × 0.25 = 15 cubic feet, or about 0.56 cubic yards (÷27). At 1.4 tons per cubic yard, that's roughly 0.78 tons — most suppliers would round this up to a minimum order (often around 1 ton, since sub-ton deliveries are uncommon), so it's worth calling ahead to confirm your supplier's minimum order size before finalizing quantity.
A second example: a small driveway base
A driveway section 40 ft × 12 ft, filled with a denser compacted base material at 5 inches deep and 1.6 tons/cubic yard density (denser, angular material suited to a load-bearing base): area is 480 sq ft, and at 5 inches (0.417 ft) deep, that's 480 × 0.417 ≈ 200 cubic feet, or about 7.4 cubic yards. At 1.6 tons per cubic yard, that's roughly 11.9 tons of base material — a full truckload for most local suppliers, and a project where getting the density figure right (by checking with the supplier) matters more than for a small path, since a 0.1 ton/cubic yard error compounds to nearly a full extra ton at this scale.
Common mistakes
Using a decorative-gravel depth for a driveway base
A 2-inch decorative depth is fine for a garden path but far too shallow to support vehicle weight without rutting and sinking over time. Driveways need a proper compacted base, typically several inches deep and often built in multiple layers — treat this calculator's default as a starting point for paths only, and increase depth substantially for anything vehicles will drive on.
Ignoring compaction when calculating loose material needed
Ordering exactly the loose volume for your target finished depth can leave you short once the material compacts underfoot or under rain. Many installers add a compaction allowance (roughly 10-20% extra) or compact the material in stages during installation, checking depth after each pass rather than assuming loose depth equals finished depth.
Forgetting to account for existing material already in place
If you're topping up an existing gravel path or driveway rather than starting from bare ground, measure the current depth and only calculate for the difference to reach your target — not a full fresh layer on top of what's already there, which would leave the surface too deep and loose underfoot.
Not accounting for edging or containment
Loose gravel spreads outward over time without a physical edge (paver edging, landscape timbers, or a trench cut) to contain it, especially on a path with foot traffic or a slope. Without containment, expect to periodically rake material back into place and eventually top up areas that have migrated outward.
Buying exactly the calculated tonnage with no buffer
Spillage during delivery and spreading, plus the compaction effect described above, mean the raw calculated tonnage is a floor, not a ceiling. Rounding up to the next half-ton or full-ton increment (however your supplier sells it) is cheap insurance against a mid-project reorder, especially since a partial-load delivery fee often costs more than the extra material would have.
Assuming all 'gravel' products have the same density
Pea gravel, crushed limestone, granite chips, and river rock can differ in density by 30% or more for the same visual volume. Always check the specific product's density with your supplier rather than relying on a generic figure if you're ordering a large or expensive quantity — see the density field's default and adjustable range above.
Measuring depth in inches but forgetting to double-check the unit toggle
Depth is a small number either way (a few inches or a few centimetres), so an accidental unit mismatch after toggling between imperial and metric is easy to miss at a glance — unlike an area error, which usually produces an obviously wrong total. Glance at the unit label next to the depth field, not just the number, before finalizing an order.
Not accounting for material lost to a weed barrier or landscape fabric underneath
A weed barrier fabric under the gravel doesn't consume gravel volume itself, but it does change how the gravel settles into the layer below — gravel over fabric tends to shift and redistribute less over time than gravel directly over bare soil, which can mean slightly less long-term top-up material is needed. It's a minor effect, but worth knowing if you're trying to explain why a fabric-backed path needed less follow-up material than an unfabriced one of the same size.
Confusing bag-sold decorative gravel pricing with bulk tonnage pricing
Small decorative gravel bags (often 0.5 cubic feet each, sold at home-improvement stores) work out to a dramatically higher price per ton than the same material bought in bulk from a quarry or landscaping supplier. Calculate your tonnage here first, then compare bulk delivery pricing against the bagged-unit cost before assuming bags are the convenient option — for anything beyond a very small accent bed, bulk delivery is almost always cheaper even after accounting for a delivery fee.
When this calculator's model stops applying
- Driveways and other vehicle-load areas: this tool's default depth (3 inches) is sized for paths, not driveways. Increase the depth substantially (commonly 4-6+ inches, often in multiple compacted layers) and consider a separate coarser base-layer material underneath the top decorative layer.
- Sloped sites: on a grade, gravel migrates downhill over time without edging or terracing, and this flat-depth model doesn't account for that redistribution — expect ongoing maintenance or install physical containment on sloped applications.
- Drainage-specific applications (French drains, trenches): these typically require a specific washed, uniform gravel size and depth driven by pipe diameter rather than the general path/driveway guidance this calculator assumes — verify against your drainage design.
- Very large areas (over roughly 1,000 sq ft, or multiple truckloads): at this scale, delivery logistics (truck capacity, multiple trips, staging space for dumped material) often become the binding constraint rather than the calculated volume alone — coordinate directly with your supplier on delivery scheduling.
- Two-layer systems (coarse base plus decorative top layer): run this calculator once per layer with each layer's own depth and density, since combining them into one calculation would misrepresent both the volume and the weight of either material.
- Extreme climates with significant frost heave: in regions with deep frost lines, some contractors specify a deeper compacted base than climate-mild regions require, specifically to reduce heave-related settling — check local landscaping guidance for frost-line-adjusted depth in your area.
- Curved or irregularly shaped paths: this calculator's area input assumes a simple rectangle. For a curved path, break it into a series of short straight segments (each treated as its own small rectangle), calculate each separately, and sum the results — a single length × average-width estimate tends to understate a path that curves substantially, since the outer edge of a curve covers more ground than the inner edge.
- Areas bordering a retaining wall or raised bed: gravel against a vertical edge often needs a slightly deeper fill near the wall to prevent erosion and settling at the joint, which a single flat depth figure doesn't capture. Treat the calculator's output as the average across the area and expect to hand-place a bit more material right at the wall line.
- Gravel used as a top dressing over an existing hard surface (e.g. a thin decorative layer over compacted base or landscape fabric): at very shallow depths (under about 1 inch), the volume math still works but the practical minimum order from most suppliers may exceed what's calculated — check minimum order sizes before assuming a small calculated volume is orderable as-is.
- Sites with poor drainage or a high water table: gravel placed over soil that doesn't drain well can sink, shift, or develop standing water in low spots regardless of how accurately the volume was calculated — a drainage assessment (and possibly a perforated pipe or gravel-specific drainage layer underneath) matters more here than getting the tonnage exactly right.
- Projects combining multiple gravel colors or sizes in a pattern (a border of one material around a field of another): calculate each material's area separately rather than estimating one combined area and splitting the tonnage by eye, since border areas are often a much smaller fraction of total area than they appear visually.
FAQ
How deep should a gravel path or base layer be?
For a walkway or light-duty path, 2 to 4 inches of compacted gravel is typical. For a driveway or anything that will carry vehicle weight, plan on a deeper base — often 4 to 6 inches or more, usually built up in multiple compacted layers ('lifts') rather than dumped and compacted all at once. This calculator defaults to 3 inches, suited to paths; increase it for driveway-grade projects.
Why does gravel weight per cubic yard vary so much between materials?
Density depends on the stone type and how angular or rounded the pieces are — angular crushed stone packs and locks together differently than smooth river rock or pea gravel, and denser stone types (like granite) weigh more than lighter materials of the same volume. This calculator's adjustable density field lets you match your specific product; check with your supplier for the exact figure if precision matters for a large order.
Should I order gravel by volume (cubic yards) or weight (tons)?
Most quarries and landscaping suppliers sell and deliver gravel by weight (tons), even though the project itself is naturally a volume calculation (area × depth). This calculator gives you both: cubic yards for planning coverage, and tons for placing your actual order with a supplier who prices by weight.
Do I need a base layer of a different material underneath the gravel?
For paths, gravel directly over compacted, weed-barrier-covered soil is often sufficient. For driveways or areas with vehicle traffic, most contractors recommend a coarser aggregate base layer (sometimes called road base or crusher run) underneath the decorative top layer of gravel, which this calculator doesn't separately account for — treat the depth you enter as the total if using a single material, or run the calculator twice (once per layer) if using a two-layer system.
Does gravel compact down after it's placed?
Yes — loose gravel typically compacts by roughly 10-20% once walked or driven on and settled by rain, more if it isn't mechanically compacted at installation. Many installers account for this by ordering slightly extra or by compacting in layers during installation rather than dumping the full depth loose and letting traffic compact it unevenly over time.
What's the difference between crushed stone and pea gravel for this calculator?
The area × depth × density math is identical either way — only the density figure changes. Crushed stone (angular, interlocking) is denser and more stable underfoot, typical for driveways and paths; pea gravel (small, rounded) is lighter, shifts more underfoot, and is more common for decorative beds or drainage applications. Adjust the density field to match whichever you're ordering.
How much extra should I order to cover spillage and uneven ground?
A common rule of thumb among landscapers is to add 5-10% to the calculated amount for an irregular or sloped area, since uneven ground means some spots need more depth than others to look level once finished. This calculator's raw figures don't include that buffer — add it yourself if your site isn't close to flat.
Can I use this calculator for a French drain or drainage trench?
The volume math works the same way (trench length × width × depth), but drainage applications typically use a specific washed, uniform-sized gravel rather than general fill gravel, and depth requirements are usually driven by the drainage pipe's diameter plus cover, not the path/driveway guidance in this calculator — check your specific drainage design for the right dimensions before ordering.
Why is my supplier's quote in tons different from this calculator's ton estimate?
Suppliers price using their own product's actual tested density, which can differ from this calculator's adjustable default. If you know your supplier's specific product density (often listed on their technical data sheet), enter it in the density field for a closer match to their quote.
Can I switch between imperial and metric partway through?
Yes — the unit toggle at the top of the calculator converts every field you've already entered, so you won't lose your measurements. Internally the tool always computes from the same canonical values regardless of which one is currently displayed, so switching back and forth doesn't introduce any rounding error into your result.
Does the density field range have limits, and why?
Yes — the adjustable density field is bounded to roughly 1.1 to 1.9 tons per cubic yard, spanning lightweight materials like pea gravel at the low end to dense crushed stone or river rock at the high end. If your supplier quotes a density outside that range, double-check the units on their spec sheet (some list density per cubic foot rather than per cubic yard, which is a common source of confusion) before assuming the calculator's bound is wrong.
How do I measure depth for a sloped or uneven area before entering it here?
Take several depth measurements at representative points across the site (not just one) and use the average as your entered depth, since a single measurement from the shallow end will under-order and one from a low spot will over-order. For anything more than mildly uneven, see the edge-case guidance on sloped sites below rather than relying on a single average depth figure.
What's the difference between 'road base,' 'crusher run,' and the gravel this calculator assumes?
Road base and crusher run are coarser, angular aggregates (often including stone dust and smaller fines) specifically chosen to compact into a dense, stable structural layer under driveways and heavy foot traffic — they're functionally different from the decorative or drainage gravel this calculator's default density assumes. If you're ordering road base specifically, ask your supplier for that product's tested density rather than using the general crushed-stone default, since fines-heavy base material can pack denser than clean crushed stone of the same nominal size.
Will this calculator tell me how many truckloads I need?
No — it only calculates total volume and weight, not delivery logistics. A standard dump truck typically hauls somewhere in the range of 10-15 tons per load depending on the truck and local regulations, so divide your calculated tonnage by your supplier's stated truck capacity to estimate trip count, or simply give the supplier your total tonnage and let them plan delivery.
Does gravel color or finish affect how much I need to order?
No — color and surface finish (polished river rock versus rough crushed stone, white marble chips versus tan pea gravel) are cosmetic and don't change the area × depth × density math. They can, however, correlate with density and price: polished decorative stone is often sold in smaller, more expensive bags rather than bulk tonnage, so check whether your chosen product is even sold by the ton before relying on this calculator's tonnage output for ordering.
How accurate does my area measurement need to be for a small residential project?
For a typical path or bed under a few hundred square feet, measuring to the nearest half-foot (or nearest 10-15 cm) is usually accurate enough, since suppliers round order sizes anyway and a small measurement error translates into a small tonnage error. For larger driveways or commercial-scale orders, more precise measurement (professional survey or careful tape-measure work at multiple points) is worth the extra effort, since the same percentage error compounds into a much larger tonnage and cost difference at scale.
Can I use this calculator for mulch or sand instead of gravel?
The area × depth × density formula works for any bulk landscaping material, but the density figure is specific to gravel and crushed stone — mulch is far lighter (often well under half the density of gravel) and sand is usually sold and priced differently again. Use this calculator's density field only if you know the correct density for whatever material you're actually ordering; otherwise use a calculator built for that specific material.
Related tools
Mulch Calculatorif your project also includes planted garden beds alongside a gravel path or base, work out mulch quantity separately.Sand Calculatorlaying pavers over your gravel base? work out the bedding sand layer that sits between the two.Paver Calculatorif the gravel is a base course for a paver patio or walkway, estimate the pavers themselves next.Grass Seed & Sod Calculatorif a gravel path is cutting through what will otherwise be lawn, work out seed or sod for the remaining area.More landscaping tools (fertilizer calculator) are planned but not yet published.