If you're ordering fill for the first time, the maths is simple but there's one thing nobody tells you: loose fill compresses by 15–25% once it's compacted. Order what you measure and you'll be 2 cubic short on the day. Here's how Gold Coast builders actually work it out — and how it fits into your wider earthworks.
The basic formula
Volume in cubic metres (m³) = length × width × depth (all in metres).
- 10m × 5m × 0.1m (100mm deep) = 5m³
- 6m × 4m × 0.15m (150mm deep) = 3.6m³
- 20m × 1m × 0.2m (driveway trench) = 4m³
That's loose volume. Now apply the compaction factor.
The compaction factor (the bit most calculators miss)
When you compact fill with a plate compactor or roller, the same material takes up less space. To get a finished compacted depth, you need to over-order by:
- Sand: + 10–15%
- Crusher dust: + 15–20%
- Road base (Type 2.1, 2.3, 2.5): + 20–25%
- Recycled concrete aggregate (RCA): + 15–25%
- Mulch and topsoil: + 5–10% (for settlement, not compaction)
Example: 5m³ of road base for a finished 5m³ pad means you actually order 6m³ (5 × 1.20).
Cubic metres vs tonnes — quick conversions
Most Gold Coast suppliers price by tonne or by cubic metre. Approximate weights:
- Sand (dry): 1.5 tonnes per m³
- Sand (wet): 1.8 tonnes per m³
- Crusher dust: 1.6 tonnes per m³
- Road base (Type 2.1, 2.3, 2.5): 2.1 – 2.4 tonnes per m³
- Recycled concrete aggregate: 1.8 – 2.0 tonnes per m³
- Topsoil: 1.2 – 1.4 tonnes per m³
- Mulch (woodchip): 0.4 – 0.6 tonnes per m³
We built a free fill calculator that handles the maths for you — punch in length, width and depth and it gives you m³ + tonnes for the most common Gold Coast materials. Find the free fill calculator here.
Common project volumes (rough guide)
Shed pad
6m × 6m × 100mm finished depth = 3.6m³ compacted. Order 4.5m³ of road base.
Standard suburban driveway
5m × 15m × 150mm = 11.25m³ compacted. Order 14m³ of road base.
Pool surround / paver bedding
30m² × 50mm = 1.5m³ compacted. Order 2m³ of crusher dust.
Garden bed top-up
20m² × 100mm = 2m³. Order 2.2m³ of garden mix or topsoil.
Trench backfill (services)
30m × 0.4m × 0.6m = 7.2m³. Order 9m³ of sand or fine fill.
Gold Coast tipper sizes — match your order to the truck
- 4-tonne tipper: ~2m³ per load (great for tight access in Mudgeeraba, Tallai, Burleigh)
- 8-tonne tipper: ~5m³ per load (most common for residential)
- Truck and dog: ~14m³ per load (driveways, big jobs, civil)
If your order is between truck sizes, ordering one full bigger truck is usually cheaper than two smaller ones (delivery fees are per-load, not per-tonne).
How to avoid ordering wrong
- Measure the finished area (length × width) in metres, not feet.
- Decide your finished compacted depth (driveways: 150mm minimum over road base; shed pads: 100mm minimum).
- Multiply for raw volume.
- Add the compaction factor for your material.
- Call us with the number — we'll suggest the right truck and confirm material specs for the job.
Get the right material delivered
If you're not sure whether you need road base, crusher dust, or RCA — give John a call on 0487 193 085 and tell him what the pad is for. We'd rather spend 5 minutes on the phone than have you redo a job. Our materials are listed with photos and per-tonne prices.