Gravel Types and Their Uses
Crushed stone (#57, 3/4 inch) is the most common driveway and drainage gravel. Its angular pieces interlock when compacted, creating a stable surface that resists rutting. Pea gravel (3/8 inch rounded) is decorative and used for pathways, playgrounds, and dog runs, but it shifts under foot and vehicle traffic. River rock (1-3 inch) is for drainage and decorative landscaping, not suitable for driving surfaces. Crusher run (mixed fines and 3/4 inch stone) compacts into a hard surface and is the best base material under driveways and patios. Decomposed granite is a fine, sandy gravel for pathways and xeriscaping.
For drainage applications like French drains and foundation drainage, use clean washed gravel (no fines) in the 3/4 to 1.5 inch range. The voids between the stones allow water to flow freely. For concrete base material, use compacted crusher run or #57 stone at 4-6 inches deep. For the concrete itself, our concrete slab calculator provides accurate volume and cost estimates. Decorative gravel for landscaping runs $40-100 per ton for specialty colors and stone types like Mexican beach pebbles or rainbow river rock.
How to Calculate Gravel Volume and Weight
Multiply length times width times depth (converted to feet) to get cubic feet. Divide by 27 for cubic yards. Multiply by density (1.4 tons per cubic yard for most crushed stone) to get tonnage. A 25x10 foot driveway at 4 inches deep: 25 x 10 x (4/12) = 83.3 cubic feet / 27 = 3.1 cubic yards x 1.4 = 4.3 tons. Add 10-15% for compaction and settling, so order 5 tons. At $40 per ton delivered, the material costs about $200.
Gravel is sold in three ways: bulk delivery by the dump truck (cheapest per ton, minimum 1-5 tons), bagged at home centers (50 lb bags at $4-8 each, convenient for small projects), and by the cubic yard from landscape supply yards. Bulk delivery is 50-80% cheaper per ton than bags. A standard tandem dump truck carries 12-16 tons and delivers to your driveway for a flat fee of $50-100 plus the per-ton cost. For projects under 1 ton, bags from the home center are practical. For larger projects, bulk delivery is the only economical choice. Use our sand calculator for the sand bedding layer that goes under pavers on top of the gravel base.
Gravel Driveway Construction
A proper gravel driveway has three layers. The subgrade is the native soil, graded and compacted. The base layer is 3-4 inches of coarse crushed stone (#2 or #3, 1.5-2.5 inch) that provides structural support. The surface layer is 1-2 inches of finer crushed stone (#57, 3/4 inch) that creates a smooth driving surface. For heavy use (trucks, RVs), increase the base to 6 inches. The total gravel depth should be 4-6 inches for residential driveways. Crown the surface (slightly higher in the center) for drainage at 1/2 inch per foot of width.
Maintenance includes regrading with a box blade or tractor once or twice a year to restore the crown and fill ruts, adding a fresh 1-inch top dressing of surface gravel every 2-3 years ($2-4 per linear foot), and controlling weeds with occasional herbicide application. A well-maintained gravel driveway lasts indefinitely, unlike asphalt or concrete which eventually need replacement. For alternative driveway surfaces, our asphalt calculator provides cost comparisons for paved options.
Gravel for Drainage Projects
French drains use gravel to create an underground channel that redirects water away from foundations and low areas. A standard French drain is 12-18 inches wide and 18-24 inches deep, filled with clean washed gravel and a perforated drain pipe at the bottom. Calculate the gravel volume: for a 50-foot long trench at 12 inches wide and 18 inches deep, subtract the pipe volume (4-inch pipe) to get about 2.5 cubic yards of gravel or 3.5 tons. Wrap the gravel in landscape fabric to prevent soil from clogging the voids.
Foundation drainage (drain tile) runs around the perimeter of the foundation footing at the base of the wall. It uses the same gravel-and-pipe system as a French drain but in a continuous loop. Estimate 3-4 cubic yards of gravel per 100 linear feet of foundation for a standard 12-inch wide by 12-inch deep drainage trench. Window wells, dry wells, and catch basins also require specific volumes of drainage gravel. Always use clean washed stone (no fines) for drainage applications so water can flow freely through the voids between stones. For the overall site grading, our excavation calculator helps plan the earthwork.
Common Gravel Calculation Mistakes
Using the wrong density factor is the most common error. Different gravel types have different weights per cubic yard: crushed limestone is 1.4 tons/CY, pea gravel about 1.3 tons/CY, and river rock about 1.2 tons/CY. Wet gravel is 10-15% heavier than dry. Using a generic 1.0 factor (which some online calculators do) underestimates the weight by 20-40%, leading to a short order and a second delivery charge. Always verify the density with your supplier.
Not accounting for compaction is the second mistake. Gravel compacts 10-20% when tamped with a plate compactor or driven over. If you need 4 inches of compacted gravel, order enough for 5 inches of loose material. The compaction factor is separate from the waste factor of 5-10% for spillage and uneven spreading. Finally, ordering by the cubic yard when the supplier prices by the ton (or vice versa) creates budget mismatches. Always confirm the unit of measure with your supplier before ordering. For the lumber used to build gravel containment borders, our lumber calculator helps estimate the wood needed.