Ordering the correct quantity of aggregate for a hardscaping or construction project requires understanding the difference between loose volume, compacted volume, and bank (in-place) volume. A cubic yard of crushed stone measured loose in the delivery truck occupies a different volume than the same material after it has been spread and compacted in place. Ignoring the swell factor and compaction ratio leads to either running short (causing project delays and additional delivery charges) or ordering too much (wasting money and creating a disposal problem).
This guide covers the volume and weight conversions that every hardscape contractor, site superintendent, and material estimator needs to know. We address the standard swell and compaction factors for common aggregate types, how to convert between cubic yards and tons, and the practical ordering considerations that ensure you get the right quantity delivered to the job site.
Swell Factors and Compaction Ratios
When aggregate is excavated from a quarry, it swells (increases in volume) because the interlocking particle structure is broken up and air fills the voids between particles. The swell factor is the ratio of loose volume to bank (in-place) volume, expressed as a percentage. Crushed stone typically has a swell factor of 10-15%, meaning 1 cubic yard in the bank becomes 1.10-1.15 cubic yards when loose. Sand and gravel swell 10-12%. Clay can swell 30-40%.
Conversely, when loose aggregate is placed and compacted, it shrinks (decreases in volume) compared to its loose state as particles are forced together and air is expelled. The compaction factor (or shrinkage factor) is the ratio of compacted volume to loose volume. For crushed stone base material compacted to 95% Modified Proctor density, the compacted volume is typically 80-85% of the loose volume, meaning you need to order 1.15-1.25 loose cubic yards for every 1 cubic yard of compacted material in place.
The practical ordering calculation combines these factors. If you need 100 cubic yards of compacted aggregate base in place, and the material compacts to 85% of loose volume, you need 100 / 0.85 = 117.6 loose cubic yards delivered. Always add a 5-10% overage allowance for waste, spillage, and measurement inaccuracy. For a paver base requiring 6 inches of compacted aggregate over 1,000 square feet: volume = 1,000 × 0.5 / 27 = 18.5 compacted cubic yards. With a compaction factor of 0.85 and 10% overage: 18.5 / 0.85 × 1.10 = 23.9 loose cubic yards to order.
Aggregate Compaction Shrink Calculator
Calculate loose material quantity needed for compacted fill. Includes swell factors, tonnage, and truck load count by material type.
Weight-Volume Conversions by Material Type
Aggregate is sold by the ton or by the cubic yard depending on the supplier, so converting between the two is a daily calculation for contractors. The weight of aggregate per cubic yard varies by material type, moisture content, and gradation. Common approximate weights (loose, per cubic yard): Crushed limestone base: 2,700-2,900 lbs (1.35-1.45 tons). Pea gravel: 2,600-2,800 lbs. 3/4" clean crushed stone: 2,500-2,700 lbs. Sand (dry): 2,600-2,800 lbs. Sand (wet): 3,000-3,200 lbs. Topsoil: 2,000-2,400 lbs.
Moisture content significantly affects weight without changing volume. Wet sand can weigh 15-20% more than dry sand. If you are buying by the ton, wet material gives you fewer cubic yards per ton. If buying by the cubic yard, moisture does not matter because volume is volume. Most quarries sell by the ton because their truck scales measure weight directly. Ask the supplier for their standard weight-per-cubic-yard conversion factor for the specific product you are ordering, as it varies by quarry source and gradation.
For hardscaping projects, the most common materials are: dense-graded aggregate base (DGA or crusher run) for paver and wall foundations (contains fines that bind together when compacted), clean crushed stone (no fines) for drainage behind retaining walls and under pavers as a bedding/setting layer, and concrete sand or manufactured stone dust for the setting bed under pavers. Each has different compaction characteristics and ordering considerations.
Aggregate Compaction Shrink Calculator
Calculate loose material quantity needed for compacted fill. Includes swell factors, tonnage, and truck load count by material type.
Compaction Methods and Testing
Proper compaction of aggregate base is essential for hardscape longevity. Insufficiently compacted base settles over time, causing pavers to shift, walls to lean, and slabs to crack. The standard compaction specification for hardscape base is 95% Modified Proctor density (ASTM D1557), which means the compacted density must reach 95% of the maximum dry density determined by a laboratory test on the specific material.
Compaction is achieved using a plate compactor (vibratory plate tamper) for granular base in confined areas and thin lifts, or a roller (smooth drum or padfoot) for larger areas and thicker lifts. The key to good compaction is lift thickness: each layer (lift) of loose material must be thin enough for the compactor to fully densify it. For plate compactors, the maximum compacted lift thickness is typically 4-6 inches. For larger rollers, 8-12 inches is achievable. Always compact in lifts, never dump the full depth and try to compact from the top.
Moisture content is critical. Aggregate compacts best at its optimum moisture content, which is the moisture level that produces maximum density for a given compaction effort. Too dry, and the particles do not slide into a dense arrangement. Too wet, and excess water prevents particles from contacting each other. For most crushed stone and gravel, optimum moisture is 6-12%. On hot, dry days, you may need to add water to the aggregate before and during compaction. On rainy days, you may need to let the material drain before compacting. A nuclear density gauge or sand cone test can verify compaction in the field, but for most hardscape projects, visual assessment (no movement under foot traffic, no visible pumping under the plate compactor) combined with proper lift thickness is sufficient.