💎 Concrete Aggregate Calculator - Free 2026

For standard concrete, approximately 1,850 lbs of coarse aggregate (gravel) and 1,250 lbs of fine aggregate (sand) are needed per cubic yard. This is based on a 1:2:4 mix ratio (cement:sand:gravel) which is common for residential projects. The exact amounts vary based on mix design strength and aggregate gradation.

Total aggregate weight is about 3,100 lbs per cubic yard, representing roughly 75% of the concrete's total weight. The remaining 25% consists of cement (approximately 565 lbs or 6 bags) and water (approximately 300 lbs or 36 gallons). Use our calculator to get precise quantities for your specific mix ratio.

Fine aggregate (sand) passes through a No. 4 sieve (4.75mm) and includes particles smaller than 3/16 inch. Coarse aggregate (gravel or crushed stone) is retained on a No. 4 sieve and ranges from 3/8 inch to 1.5 inches. Both are essential for concrete mix design, with fine aggregate filling voids and coarse aggregate providing structural strength and volume.

Fine aggregate improves workability and finishability, fills spaces between coarse particles, and reduces segregation. Coarse aggregate provides bulk volume economically, contributes to compressive strength, and reduces shrinkage cracking. Proper balance between both types creates dense, durable concrete meeting ACI 318 standards for structural applications.

The most common ratios are 1:1.5:3 (high strength, 4000+ PSI), 1:2:4 (standard residential, 3000-3500 PSI), and 1:3:6 (lean mix, 2500 PSI). The ratio represents cement:sand:gravel by volume. For structural concrete, 1:1.5:3 or 1:2:4 is recommended. The choice depends on the intended application, required strength, and local building codes.

The 1:2:4 ratio is most versatile for typical residential work including driveways, patios, and foundation slabs. It provides adequate strength (3000-3500 PSI) at reasonable cost. High-traffic commercial areas require 1:1.5:3 for 4000+ PSI strength. Non-critical applications like walkways can use economical 1:3:6 lean mix. Always consult engineer specifications for structural projects.

Calculate total concrete volume needed, then apply the mix ratio. For a 1:2:4 mix, total parts = 1+2+4 = 7. If you need 1 cubic yard: cement = 1/7 × 27 cu ft = 3.86 cu ft, sand = 2/7 × 27 = 7.71 cu ft, gravel = 4/7 × 27 = 15.43 cu ft. Convert to weight: sand ≈ 100 lbs/cu ft, gravel ≈ 100 lbs/cu ft. Add 5-10% waste factor.

For example, a 10 cubic yard project with 1:2:4 ratio needs: Sand = (2/7) × 10 × 27 cu ft = 77.1 cu ft = 7,710 lbs = 3.86 tons. Gravel = (4/7) × 10 × 27 cu ft = 154.3 cu ft = 15,430 lbs = 7.72 tons. Add 10% waste: Order 4.25 tons sand and 8.5 tons gravel. Our calculator handles these conversions automatically with moisture adjustments.

Aggregates should be in a saturated surface-dry (SSD) condition - internal pores filled with water but surface dry. Bone-dry aggregates absorb mixing water, reducing workability and strength. Very wet aggregates add excess water, increasing the water-cement ratio and reducing strength. Test aggregate moisture content and adjust mixing water accordingly, typically reducing by 4-8% for wet sand.

To achieve SSD condition, wet aggregates should be stockpiled and allowed to drain for several hours. For typical delivered sand with 5% moisture content, reduce mixing water by approximately 5% of sand weight. If using 2,000 lbs sand, subtract 100 lbs (12 gallons) from design water. Failure to adjust causes weak concrete - this is why professional ready-mix plants constantly monitor aggregate moisture.

For most residential concrete, 3/4 inch maximum aggregate size is standard. Smaller projects (under 4 inches thick) use 3/8 to 1/2 inch aggregate. Structural concrete typically uses 3/4 to 1 inch. Maximum aggregate size should not exceed 1/3 of slab thickness or 3/4 of spacing between reinforcement bars. Larger aggregates reduce cement requirements but require proper vibration for consolidation.

A 4-inch thick patio slab should use maximum 1.33-inch aggregate (4 ÷ 3), but 3/4 inch is practical for good consolidation without vibration. Thin toppings under 2 inches require 3/8 inch maximum. Heavy structural elements 12+ inches thick can accommodate 1.5-inch aggregate economically. Proper sizing ensures aggregate particles fit between rebar without creating voids or honeycombing in finished concrete.

In 2026, coarse aggregate (gravel) costs $30-$50 per ton delivered, while fine aggregate (sand) costs $25-$45 per ton. Prices vary by location, aggregate type, quality, and delivery distance. Crushed stone is typically more expensive than natural gravel. Bulk purchases (10+ tons) often receive 10-15% discounts. Local quarries usually offer better prices than landscape suppliers.

For a typical 10 cubic yard residential project requiring 4 tons sand and 8 tons gravel, expect to pay $140-$180 for sand plus $240-$400 for gravel, totaling $380-$580 for aggregates alone. Add $75-$150 delivery fee depending on distance. Urban areas pay 20-30% more than rural locations. Always get quotes from multiple suppliers and ask about contractor discounts for large projects.

Yes, recycled concrete aggregate (RCA) can replace up to 30% of natural coarse aggregate in most applications without significant strength loss. For non-structural projects, up to 100% replacement is acceptable. RCA has higher water absorption (5-10% vs 1-2% for natural aggregate), so adjust mixing water. ACI 555R provides guidelines. RCA costs 20-40% less than virgin aggregate and is environmentally sustainable.

When using RCA, pre-soak aggregates to SSD condition before batching to prevent excessive water absorption during mixing. Strength reduction is typically 5-15% for 30% replacement, 15-25% for 100% replacement. RCA works well for driveways, parking areas, and base layers. Avoid RCA for structural beams, columns, or high-strength applications unless specifically designed by engineer. Environmental benefits include reduced landfill waste and lower carbon footprint from quarrying.