Road Aggregate Calculator: Free Online Road Aggregate Calculator

Use our free road aggregate calculator to determine how much crushed stone base and sub-base material you need for a road or driveway project. Built for contractors and civil engineers, this tool converts your road length, width, and aggregate depth into total area, volume in cubic yards, and weight in tons.

How to use this calculator.

1. Enter the road length. Input the total length of the road or driveway section in feet.
2. Enter the road width. Input the paved or graded width of the section, in feet.
3. Set the aggregate depth. Enter the compacted depth of the base or sub-base layer, in inches. Road base typically runs 6-12 inches.
4. Review your results. The calculator displays road area, aggregate volume, and aggregate weight instantly.
5. Print or save. Use your browser's print function for a jobsite-ready material order sheet.

How do you calculate road aggregate base material?

To calculate aggregate weight, multiply the road area (length × width) by the depth (converted to feet), convert the result to cubic yards, then multiply by the average weight of compacted aggregate per cubic yard.

Area (sq ft) = Length (ft) × Width (ft)

Volume (cu yd) = Length (ft) × Width (ft) × Depth (in) ÷ 12 ÷ 27

Weight (tons) = Volume (cu yd) × 1.4

Where:

• Length and width: The dimensions of the road or driveway section, in feet.
• Depth: The compacted thickness of the aggregate base or sub-base layer, in inches.
• 1.4 tons/cu yd: The average density of compacted road base aggregate, equal to approximately 2,800 lb per cubic yard. Actual density varies by stone type and gradation.

Example calculation.

Let's calculate the aggregate base needed for a rural access road.

Scenario: You're building a 200 ft long, 20 ft wide gravel access road with 6 inches of compacted crushed stone base.

1. Calculate the area: 200 ft × 20 ft = 4,000 sq ft
2. Convert depth to feet: 6 inches ÷ 12 = 0.5 ft
3. Calculate volume in cubic feet: 4,000 sq ft × 0.5 ft = 2,000 cu ft
4. Convert to cubic yards: 2,000 cu ft ÷ 27 = 74.07 cu yd
5. Calculate weight in tons: 74.07 cu yd × 1.4 = 103.7 tons

Result: You need approximately 104 tons of crushed stone base for this access road, before adding a waste factor.

Tips from the field.

• Compact in lifts. Spread and compact aggregate base in layers no thicker than 4-6 inches; a single deep lift will not compact uniformly all the way through.
• Check the subgrade first. Soft, wet, or poorly drained subgrade undermines the base regardless of how much stone you add on top. Over-excavate and stabilize soft spots before placing base.
• Match depth to traffic load. Light-duty driveways often use 4-6 inches of base; highways and heavy-truck routes commonly specify 8-12 inches or more per DOT standards.
• Use angular, not rounded, stone. Crushed stone with angular faces interlocks under compaction; rounded gravel shifts and ruts more easily under load.
• Order 5-10% extra. Spillage, over-excavation, and uneven grading consume more material than the flat math suggests.
• Plan for drainage. Crown the road surface or grade toward ditches so water sheds off the base rather than saturating it; a saturated base loses much of its load-bearing capacity.

Disclaimer: This calculator provides estimates for planning purposes only. Actual aggregate requirements vary based on subgrade conditions, compaction, gradation, and site-specific engineering. For structural road designs, consult a licensed civil engineer. PavementCalculator.com assumes no liability for material overages or shortages.