Soil swell calculator
Enter the bank volume and soil type. You get the loose volume to haul and the volume it fills once compacted.
Loose volume
16.349 yd³
Net measurement: 13.08 yd³ · Waste 25 %
- Loose volume (swelled)16.349 yd³
- Compacted volume11.772 yd³
- Swell factor1.25
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How it's calculated (visible formula)
loose = bank × (1 + swell); compacted = bank × compaction factor
- Net geometric measurement, no waste.
- Adjustable waste % for cuts and breakage.
- Purchase rounded up to sellable units (boxes, bags, buckets, boards).
How to calculate it, step by step
- Work out the bank volume (in place, undisturbed).
- Identify the soil: sand, gravel, common earth, clay or rock.
- Apply swell for the loose volume that goes on the truck.
- Apply the compaction factor for how much it fills once compacted.
- Use loose for hauling and compacted for backfill.
Typical factors by soil
| Soil | Swell | Compacted / bank |
|---|---|---|
| Sand | 12% | 0.95 |
| Gravel | 12% | 0.95 |
| Common earth | 25% | 0.90 |
| Clay | 35% | 0.85 |
| Blasted rock | 50% | 1.30 |
Worked example: 13 yd³ (10 m³) of common earth
- 25% swell → 16.3 yd³ loose
- Compacted: 13 × 0.90 = 11.8 yd³
→ Haul 16.3 yd³; it backfills 11.8 yd³.
Common mistakes
- Ordering trucks from the plan volume.
- Assuming excavated soil backfills the same space once compacted.
- Using sand factors for clay.
Pro tips
- For mixed soils, use the dominant soil's factor or weight by volume.
- Wet soil swells a bit less and weighs more — watch truck payload.
- Compact structural fill in 8–12 in lifts.
- Ask for Proctor testing if the fill supports slabs or roads.
From calculation to quote
Add labour, overhead and your margin, and generate the professional PDF.
FAQs
- What's the difference between swell and shrinkage?
- Swell is the increase when dug; shrinkage is the decrease when compacted.
- Why does compacted rock take more space?
- Broken fragments never fit together as tightly as solid rock.
- How do I refine the factor?
- Use your geotechnical report or weigh a known load.
- What is bank volume?
- The volume soil occupies in its natural state, before digging.
- Why does clay swell so much?
- Digging breaks it into clods with lots of voids between them.
- How much does fill compact?
- About 10–15% relative to bank volume with good compaction.
Sources and standards
Maintained by Srikanta M · Formula v1.0.0 · Verified 2026-09-10 · Updated 2026-09-10 · Limits: quantity estimation, not structural design or site supervision.