📊 Swell & Shrinkage Calculator

The Three Measures Explained

Every earthwork job deals with three states of material — and they all have different volumes:

• Bank Measure (BCY): Material as it sits undisturbed in the ground. This is the baseline — what contracts typically use for payment.
• Loose Measure (LCY): Material after digging — it's been broken up and has air voids, so it takes up more space. This is what fills your trucks.
• Compacted Measure (CCY): Material after it's been placed and compacted in a fill — voids are crushed out, so it takes up less space than bank.

Real-World Example

Start with 100 bank cubic yards (BCY) of common soil (25% swell, 10% shrinkage):

• In the truck: 100 × 1.25 = 125 LCY — you need more trucks than you think
• In the fill after compaction: 100 × 0.90 = 90 CCY — it won't fill as much area as you dug

Why This Matters

• Truck count: Calculate loads using loose volume, not bank volume.
• Fill quantity: Order bank material based on compacted volume needed — you'll need MORE bank yards than fill yards.
• Contracts: Most government and mining contracts pay in bank measure. Know your factors before you bid.
• Rock shrinks less in compaction, but swells a lot when blasted — 65% swell means 10 cy of rock in the ground becomes 16.5 cy in a truck.