Free online tool • Feet or miles
Gravel Road Calculator
This gravel road calculator works out how many tons, cubic yards and truckloads of gravel a new road, farm lane or long private driveway needs. Enter the road length in feet or miles, the width and the compacted depth to get an order quantity and cost.
How Much Gravel Does Your Road Need?
How the Gravel Road Calculator Works
A gravel road is a long, thin rectangle, so the maths is the same as any gravel estimate — length times width times depth — just with much bigger numbers. The gravel road calculator converts everything to feet, multiplies out the volume, and turns it into the tonnage a quarry will load.
1. Convert the road length to feet
One mile is 5,280 feet and one kilometer is 3,281 feet. A quarter-mile private road is 1,320 feet long. Measure along the centerline, and add any turnarounds or passing bays as separate rectangles using the known-area option.
2. Multiply by width and depth
Multiply length by width to get square feet, then multiply by the compacted depth in feet (inches ÷ 12). A 1,000 ft road that is 12 ft wide and 6 inches deep holds 12,000 × 0.5 = 6,000 cubic feet of gravel.
3. Convert cubic feet to cubic yards
Divide by 27. The same road needs 6,000 ÷ 27 = 222 cubic yards.
4. Convert cubic yards to tons
Multiply by the bulk density of the road gravel. Crusher run and road base with fines weigh about 1.50 tons per cubic yard, so 222 × 1.50 = 333 tons. Add 10 percent for compaction and edge loss and you order about 367 tons, or 25 loads on a 15-ton tri-axle truck.
Gravel Road Tons per Mile
For long rural roads it is easier to think in tons per mile. The table assumes crusher run at 1.50 tons per cubic yard and no waste allowance — add 10 to 15 percent before ordering.
| Road width | 4 in deep | 6 in deep | 8 in deep |
|---|---|---|---|
| 10 ft | 978 tons | 1,467 tons | 1,956 tons |
| 12 ft | 1,173 tons | 1,760 tons | 2,347 tons |
| 14 ft | 1,369 tons | 2,053 tons | 2,738 tons |
| 16 ft | 1,564 tons | 2,347 tons | 3,129 tons |
| 20 ft | 1,956 tons | 2,933 tons | 3,911 tons |
A shortcut worth remembering: every inch of depth on a 12 ft wide road costs about 293 tons per mile. Divide any figure by 52.8 to get tons per 100 feet.
How Deep Should a Gravel Road Be?
Depth is the input that changes a gravel road estimate the most, and the right figure depends on the traffic and the soil underneath.
Light traffic and farm lanes
A field lane or a private road that sees cars and the odd pickup can get by with 4 inches of compacted crusher run over firm, well-drained soil.
Private roads and long driveways
Plan on 6 inches of compacted road gravel. Many builders lay it as two lifts: 4 inches of larger base stone, then 2 inches of surface gravel with fines that packs into a hard, shedding crust.
Heavy trucks and soft ground
Roads carrying delivery trucks, logging equipment or farm machinery, or built over clay, need 8 to 12 inches in total, usually with geotextile fabric between the subgrade and the first lift so the stone does not punch into the soil.
Best Gravel for a Gravel Road
Road gravel is not decorative stone. A good gravel road surface needs angular pieces for strength, plus enough fine material to bind them together and shed rain.
- Crusher run / dense graded aggregate — the default choice for both base and surface. Compacts hard, about 1.50 t/yd³.
- Road base (aggregate base course) — a specified, tested gradation sold by most quarries for roads. Similar weight to crusher run.
- Surface gravel with fines — a top course with more clay-sized binder so the gravel road surface sets up rather than staying loose.
- #3 or #4 base stone — large clean stone for the bottom lift on soft ground. Never use it as the driving surface.
- #57 stone — clean and free-draining, but it stays loose and ruts on a road. Use it for drainage crossings, not the running surface.
- Asphalt millings — recycled and cheap; they bind in summer heat. Check local rules before placing them near water.
Gravel Road Cost
Road gravel is the cheapest aggregate a quarry sells — typically $15 to $35 per ton at the pit. On a road job the freight often costs as much as the stone, so the gravel road calculator counts truckloads and prices delivery per load.
Using the 1,000 ft example: 367 tons at $25 is about $9,200 in material, plus 25 loads at $120, about $3,000 in delivery, for roughly $12,200 — or around $64,000 per mile at the same width and depth. Grading, culverts and ditching are extra and vary widely, so enter a per-square-foot grading rate in the calculator if a contractor has quoted one.
Crown and Drainage on a Gravel Road
Water is what destroys a gravel road. Shape the surface with a crown of about 4 percent — roughly half an inch of fall per foot from the centerline to each edge — so rain runs off to the ditches instead of soaking in and forming potholes. A 12 ft road should sit about 3 inches higher in the middle than at the shoulders. The crown does not change the gravel quantity much, but it is why a waste allowance of 10 to 15 percent is sensible: grading the crown moves material to the edges, where some of it is lost.
Related Gravel Calculators
These tools use the same volume and density maths for neighbouring jobs:
- Driveway gravel calculator — sizes a residential driveway by layer
- Gravel driveway cost calculator — adds excavation, fabric and labor to the material cost
- Crusher run calculator — the standard road base and surface material
- Gravel base calculator — compacted base under slabs, pavers and sheds
- Cubic yards to tons calculator — convert a road volume to a tonnage order
- How deep should gravel be? — depth guidance for every project type
Depth and crown guidance on this page follows common county road practice; the EPA Gravel Roads Maintenance and Design Manual covers road shape, drainage and surface gravel in detail.
Gravel Road FAQ
How many tons of gravel do I need for a mile of road?
A 12 ft wide road at 6 inches deep needs about 1,760 tons of crusher run per mile, or roughly 1,940 tons with a 10 percent allowance. At 4 inches deep it is about 1,173 tons, and each additional inch of depth adds about 293 tons per mile.
How deep should gravel be on a road?
Use 4 inches of compacted gravel for light-traffic farm lanes, 6 inches for private roads and long driveways, and 8 to 12 inches with geotextile fabric where heavy trucks run or the soil is soft clay.
What is the best gravel for a gravel road?
Crusher run or road base with fines is best because the angular stone locks together and the fines bind the surface. Clean stone such as #57 drains well but stays loose and ruts, so keep it for drainage areas rather than the driving surface.
How many truckloads of gravel do I need for a road?
Divide the total tons by the truck capacity. A tandem dump truck carries 13 to 15 tons and a tri-axle 15 to 18 tons, so a 1,000 ft road needing 367 tons takes about 25 loads on a 15-ton truck.
How much does it cost to gravel a road?
Road gravel costs about $15 to $35 per ton plus $80 to $200 delivery per load. A 12 ft wide road at 6 inches deep typically runs $50,000 to $75,000 per mile for material and delivery before grading, ditching and culverts.