Article — Gravel Driveway Calculator
Gravel driveway calculator: tonnage, depth, and cost made simple
A gravel driveway calculator converts length, width, and depth into the cubic yards or tons of crushed stone, pea gravel, or crusher run needed. Volume in cubic yards = (length in ft × width in ft × depth in inches) ÷ 324. Crushed stone #57 weighs 1.35 short tons per cubic yard. A standard 50 × 12 ft driveway at 6 inches deep needs 11.1 cubic yards of gravel, or about 17 tons after a 15% compaction allowance.
The hard part of any gravel driveway project is not pouring the gravel — it is planning the order. Order too little and you make a second trip for a short-load fee. Order too much and you stockpile material that washes away. The math behind the calculator gives you the exact tonnage; the practice behind the math is picking the right gravel type and depth for your soil and traffic.
The gravel driveway formula
Volume comes first. In US units, cubic yards equal length in feet times width in feet times depth in inches divided by 324. The 324 is 27 cubic feet per cubic yard times 12 inches per foot, baked into one constant so depth in inches works directly with length in feet.
yd³ = (L_ft × W_ft × D_in) / 324 US unitsm³ = L_m × W_m × D_m metrictons = yd³ × 1.35 crushed stone #57order = volume × 1.15 compaction +15%Weight follows volume through density. Crushed stone #57 (the most common driveway gravel) runs 1.35 short tons per cubic yard. Crusher run is denser at 1.45 t/yd³; pea gravel is lighter at 1.25; river rock is lighter still at 1.20. Multiply the volume by density and you have the tonnage to order.
How deep should gravel go on a driveway
The default answer is 4 to 6 inches for a single-layer driveway, 12 to 18 inches total for a three-layer build. Single-layer driveways need refreshing every 6 to 18 months because the loose surface migrates under tires. Three-layer builds last 3 to 5 years between top-ups because the load spreads across a compacted base.
The thinner end of the range works on firm subgrade with light residential traffic. The thicker end is for clay soils, frequent delivery trucks, or RV parking. If you do not know your soil, dig a test hole — gravel over clay needs a geotextile fabric and 6+ inches; gravel over sandy loam works at 4 inches.
Gravel types for driveways
Four grades cover almost every driveway project. Crusher run (also called quarry process or QP) is the densest at 1.45 t/yd³, packs hard, and is the right material for the sub-base layer. Crushed stone #57 is the workhorse: 3/4-inch angular pieces that drain well and carry load — default to it if you only buy one grade. Pea gravel is small (3/8-inch), rounded, and pretty — the surface course on top of a base. River rock is decorative, expensive, and migrates under vehicle weight; reserve it for non-driving areas.
The Romans built gravel roads in four layers more than 2,000 years ago: statumen (large stones), rudus (broken stone), nucleus (gravel and mortar), and summum dorsum (paving stones). Modern gravel driveways follow the same principle — coarse below, fine above. Millions of miles of gravel roads still operate worldwide (FHWA estimates ~2.2 million miles of unpaved roads in the US alone) because the design works at any scale.
Three-layer gravel driveway design
The professional standard is sub-base, base, surface. Six inches of compacted crusher run forms the sub-base directly on the geotextile-wrapped subgrade. Four to six inches of #57 crushed stone forms the base course, compacted and graded for crown. Four to eight inches of pea gravel or angular surface stone tops it off, raked to a 2% cross-slope for drainage.
Total depth runs 14 to 20 inches. Material cost roughly doubles versus a single-layer install, but life expectancy quadruples and recurring top-up costs drop to almost nothing. For long driveways (100+ feet) the math favors the three-layer approach by year three.
Gravel driveway cost in 2026
Bulk crushed stone delivered runs $25 to $55 per ton in the US Midwest and South, $35 to $70 on the coasts. Pea gravel and river rock are $40 to $80 per ton because they get washed and sorted multiple times. Add $50 to $150 for short-load delivery (under 15 tons), or pick up a smaller load yourself if you have a half-ton pickup and a yard of cubic capacity.
- Material per ft² = $0.50 to $1.30 for a 4 to 6 inch single layer of crushed #57
- Three-layer build = $1.50 to $3.50 per ft² including all three grades
- Geotextile fabric = $0.20 to $0.50 per ft² (pays for itself the first time you skip a replacement)
- Bulk delivery fee = $50 to $150 for under 15 tons, free above
- Contractor install = $1.50 to $5.00 per ft² over the material cost
- Edging = $2 to $5 per linear foot for treated lumber, stone, or steel
Compaction and settlement
Loose gravel compacts 10 to 20% in the first months of use. Vehicle tires push the angular pieces together, eliminating void space. The calculator applies a default +15% compaction allowance to the ordered volume; bump it to +20% for delivery trucks, contractor vehicles, or RVs that load the surface heavily.
If you have access to a plate compactor or vibratory roller, run it over each layer before adding the next. Mechanical compaction pre-shrinks the gravel by 8 to 12% — you order slightly more material but skip the seasonal settling and the gravel locks in place faster. Rental: $50 to $80 per day for a 200 lb plate compactor.
Drainage and grading
Aim for a 2% cross-slope minimum so water sheets off the driveway instead of pooling. On long driveways, add a swale on the uphill side and a culvert at any low point. Gravel that holds standing water washes the fines out of the base within one rainy season — the result is potholes that grow every winter and a driveway that needs full reconstruction in three years instead of ten.
River rock looks pretty but its rounded shape means it does not lock together — it just shifts under load. Use angular crushed stone for the base and middle layers; save the rounded material for decorative top dressings only. Mixing the two in the base produces a driveway that ruts at the first heavy rain.
Common gravel driveway mistakes
Skipping the geotextile fabric on clay or soft soil is the number-one mistake. The fabric stops gravel from mixing into the subgrade and stops weeds from coming up through the surface. It costs $0.20 to $0.50 per ft², takes 30 minutes to roll out for a typical driveway, and adds years of life.
The second mistake is over-thin single-layer installs. Four inches of crushed stone over soft soil is gone in a year — the tires push the gravel into the dirt. Bump single-layer installs to 8 inches minimum on soft soil, or add a 6-inch crusher-run sub-base and treat the install as a real two-layer build.
Third is rounded gravel for the wrong purpose. River rock and pea gravel migrate under vehicle loads, leaving bare ruts where tires repeatedly track. Use angular crushed stone (#57 or crusher run) for any layer that carries vehicle weight.