SiteworkMath — cubic-yard markConstruction math from people who’ve thrown the wheelbarrow.
Tools · No. 06Gravel · Cluster anchor

Gravel calculator — yards, tons, and the compaction cushion.

Gravel math is length × width × depth, divided by 27 for cubic yards. A 12-foot by 40-foot driveway with 6 inches of crusher-run base comes out to 8.9 cubic yards — about 14 tons at the supplier. Type your dimensions, pick the use case, and the calculator does the math, the tons conversion, and the compaction cushion crusher run needs.

Most gravel orders go into one of four jobs: a driveway base or top dressing, a walkway, a French drain trench, or a decorative bed. The right gravel for each is different — angular crusher run for compactable subbase, clean #57 for drainage, rounded pea for foot comfort, river rock for the eye. The notebook below tells you what to call the dispatcher with — and which type of gravel actually belongs in your job.

Driveway subbase — compactableMode · 4-6″ compacted base (order LOOSE × 1.20)
feet
Long edge of the area you're filling.
feet
Short edge.
inches
USDA NRCS spec: 4-6″ compacted #3 stone subbase. Order 6″ LOOSE to land at ~5″ compacted.
percent
7% default. Bump to 12% on rough or sloped fill.
Exact · 8.89 yd³
Tons · 15.14
Type · Crusher run (compactable)
Compaction note · Crusher run loses 15-20% volume between loose and compacted. The depth above is what the supplier delivers — multiply your design depth by 1.20 to get the order depth.
Material order cushion
The math8.89 yd³480 sq ft × (6″/12) / 27 = 8.89 yd³
What I’d actually order9.75 yd³or 15.14 tons at the dispatcher
Why the cushionGravel loses a fraction in transit (settling on the truck, spillage at the chute), spread inefficiency at corners and edges, and weight tolerance at the supplier (a 5-yard ticket may show up at 4.85). The cushion absorbs all three so the spread depth lands where you measured.
When NOT to over-orderDon't double-cushion. The 7% default already covers settle-in-transit, corner spillage, and supplier tolerance — adding another 5% on top means a pile of leftover gravel hardening on your driveway. If the project is genuinely uncertain, schedule a second smaller delivery rather than over-ordering once.
Quick tipsWhat I'd want you to know in 60 seconds
Worked example12×40 driveway base, two-layer build

A 12×40 residential driveway, two layers of stone, one truck of base.

480 square feet of driveway. Base layer: 6 inches loose crusher run. Volume math: 480 × (6/12) / 27 = 8.89 cubic yards exact, or 13.80 tons at the 115 lb/ft³ density. Add the 7% cushion and the practical order is 9.75 yards — about 15.14 tons. I'd call Vulcan or a regional Chicago-metro yard and ask for 15.5 tons loose to leave a working cushion, with delivery confirmed for the morning so I have all day to spread and compact before any weather.

Top dressing: 2 inches of #57 angular stone over the compacted base. Volume math: 480 × (2/12) / 27 = 2.96 cubic yards exact at 100 lb/ft³ → about 4.0 tons. Add cushion → 3.25 yards or 4.39 tons practical — a separate delivery, but a smaller one. Total across both layers: about 13 yards, 19-20 tons. Geotextile fabric goes down BEFORE the base. On heavy Chicago-suburb clay, skipping that fabric is the single biggest reason gravel driveways turn back into mud strips by year three.

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Quick answers about SiteworkMath's calculators and material take-offs — concrete yardage, topsoil + mulch volume, tile box-count, deck-surface materials. Free, no signup. Not structural-engineering or code advice — for joist / beam / footing / permit decisions, talk to a structural engineer, licensed contractor, or your local building department.

Hi, I'm the SiteworkMath assistant. I answer questions about the calculators and guides on this site — concrete yardage, topsoil, mulch, tile, and decking material math. I'm not a structural engineer or a licensed contractor; I'm a calculator built around the math that James Wu — Chicago-area flipper — uses on his own jobs. For structural decisions (joist sizing, beam spans, footing depth in your soil + climate, anything that needs a permit) talk to a licensed structural engineer or your local building department.

How I'd actually use this on a flip

Gravel orders show up on flips at three predictable points: the new-construction site prep (driveway, basement-perimeter drainage, garage pad subbase), the rehab exterior pass (replacing a tired asphalt driveway with stone, or running a French drain to fix a wet basement), and the landscaping closeout (decorative beds around the foundation, pea-gravel walkway from driveway to back patio). The math is the same in all three — what changes is which type of gravel and what underlayment goes down first.

On a driveway pour or replace, my default is two trucks: one of crusher run for the base, one of #57 for the top. Geotextile fabric goes down before the first truck. Compaction matters as much as the order quantity — a vibratory plate compactor passes twice over each 2-inch lift, and the calculator's 1.20 multiplier on loose depth assumes you're actually compacting. If you skip compaction the driveway settles into ruts the first time a delivery truck rolls over it.

On a French drain to fix a wet basement, the math gets easier because the trench dimensions are tight. A 30-foot perimeter run at 12 inches deep × 12 inches wide is right at 1.11 yards exact — 1.25 yards practical, about 1.69 tons. That's below the 5-yard supplier minimum, so I order from a smaller landscape yard or pay the small-load surcharge. Geotextile wraps the trench so soil fines don't clog the drain over time; the perforated pipe goes in the middle of the stone column.

Where this number breaks down

A few traps that put the calculator on the wrong side of the order:

Methodology

Every number on this page traces to one of three layers — site arithmetic for the volume math, supplier spec sheets for per-type bulk densities (cross-checked against Omnicalculator and InchCalculator industry references), and USDA NRCS aggregate-surfacing standards for the driveway depth + geotextile guidance. The per-cluster sourcing tier in methodology spells out which sources back which kinds of claims.

Show the formulas
  • Volume: (L ft × W ft × T″ / 12) / 27 = cubic yards.
  • Tons: yd³ × 27 ft³/yd³ × density (lb/ft³) / 2000 lb/ton. Densities used: pea 96 lb/ft³, #57 clean 100, crusher run 115 loose, decorative river rock 95.
  • Practical order: exact × (1 + waste%/100), rounded UP to the next 0.25 yd³. Default 7% cushion absorbs transit settle, corner spillage, and supplier weight tolerance.
  • Compaction loss (compactable types only): 17.5% loose-to-compacted on crusher run / road base. Order loose depth = design depth × 1.20 to land at the design depth after compaction.

Frequently asked

How much gravel do I need for a driveway?

A typical residential driveway needs 8 to 12 inches of total compacted depth in three layers — a 4-6 inch compacted crusher-run subbase, a middle layer of #3 stone, and a 2-inch #57 stone top dressing (USDA NRCS Earth and Aggregate Surfacing Design Guide). For a 12-foot by 40-foot driveway with a 6-inch loose crusher-run base, that's about 8.9 cubic yards or 13.8 tons before cushion, 9.75 yards or 15.14 tons practical at the dispatcher. Use the calculator above for any driveway dimensions; the engine swaps gravel type and depth by use case.

How many tons of gravel are in a cubic yard?

Most gravel weighs 1.4 to 1.7 tons per cubic yard. Pea gravel sits at the lower end (about 1.30 tons/yd³ at 96 lb/ft³); crusher run at the higher end (about 1.55 tons/yd³ loose at 115 lb/ft³, denser still after compaction). #57 angular drainage stone is the typical residential mid-point at roughly 1.35 tons/yd³ (100 lb/ft³). Aggregate suppliers bill by the ton; landscape suppliers sometimes quote yards. The calculator above shows both numbers so you can confirm with whoever's dispatching.

What size gravel is best for a driveway?

Use crusher run (also called road base or quarry process) for the subbase — the mix of fines and ¾-1 inch angular pieces packs and compacts into a stable load-bearing layer. Use #57 stone (¾ inch clean, no fines) for the top dressing because it stays loose, drains, and gives the surface its finished crunch. Don't use rounded pea gravel as a driveway top — vehicle tires shove it into ruts within a season. The calculator's Driveway base preset defaults to 6 inches of crusher run; the Driveway top preset defaults to 2 inches of #57.

How thick should a gravel driveway be?

USDA NRCS spec for residential gravel driveways is 8 to 12 inches of total compacted depth in three layers. On moderate clay or loam soil, the 4-6 inch compacted crusher-run subbase should be at the upper end (6 inches) with a geotextile separation fabric underneath, landing total compacted thickness at 10-12 inches. On heavy clay the subbase has to be at least 8 inches and geotextile is non-negotiable. Skipping the geotextile lets fines from the soil migrate up into the gravel within a few rainy seasons; the driveway turns into a soft strip that won't drain.

Do I need a weed barrier or geotextile fabric under gravel?

For a driveway: yes, geotextile is required by NRCS spec on heavy clay and recommended everywhere else. Use a non-woven fabric rated for driveway use (minimum 4 oz per square yard), overlap joins by at least 12 inches, and pin the edges. For decorative beds: a permeable landscape fabric helps with weeds and lets water through, but the bigger weed-control move is depth — 3 inches of mulch or stone over a clean prep does more than fabric over a half-prepped surface. Don't use plastic sheet under gravel; it traps water and the gravel migrates downhill on the slick layer.

How much does a yard of gravel cost?

Pricing varies by region, gravel type, and quantity, but as a Chicago-metro 2026 rule of thumb: pea gravel runs $50-65 per cubic yard delivered (5-yard minimum), #57 angular stone $40-55, crusher run $35-50, and decorative river rock $80-150 depending on size and color sort. Bagged from a big-box at 0.5 cubic feet per bag is roughly 4-7x the per-yard price — practical only for small projects under a yard. The calculator output above doesn't include price; call your closest aggregate supplier for the day's pricing and confirm both yards and tons on the dispatch ticket.

What I'd do next

  1. Topsoil for the lawn restore

    After the gravel driveway and beds, the lawn restore is the closeout. The cushion math is similar; the depth presets are different.

  2. Concrete yardage (slab, footing, post hole)

    If the driveway is concrete instead of gravel — or if the gravel base is going under a slab — step over to the concrete calc.

  3. Whole-project budget (rehab)

    A driveway is one line on a bigger budget. The flagship surfaces every line for a residential gut rehab.

Also in this cluster


By James Wu. Volume math is site arithmetic, formulas above. Per-type loose bulk densities are midpoints from supplier spec sheets cross-checked against Omnicalculator (105 lb/ft³ default) and InchCalculator (1.4-1.7 tons/yd³ range). Driveway depth specs and geotextile guidance from USDA NRCS TN 210-AEN-04 — Earth and Aggregate Surfacing Design Guide (August 2017) and NRCS Construction Specification 495 — Geotextile. Earthfill + gravel-fill construction practices from NRCS Construction Specification 423 — Earthfill and Gravel Fill. Compaction loss range (15-20% loose-to-compacted on crusher run) cross-referenced against InchCalculator's “How to Account for Overage and Compaction” section. Engine logic in lib/sitework/gravel.ts. Not structural-engineering advice — for soil-bearing capacity, frost-line drainage, or any base prep under a structural slab, consult the local building inspector or a geotechnical engineer. Full methodology.