Road Base Calculator — Volume & Tonnes of Aggregate
Enter the area dimensions and layer depth to find how many cubic metres and tonnes of road base, crushed rock or compacted aggregate to order. A 30% compaction factor is included so you order enough loose material to compact down to the required depth.
m
m
Depth unit
kg/m³
Includes 30% compaction factor — loose material compacts by ~23% once laid
- 1
Depth in metres
150 mm ÷ 1,000 = 0.15 - 2
Compacted volume
10 × 3 × 0.15 m = 4.5 - 3
Order volume (+ 30% compaction)
4.5 × 1.30 = 5.85Loose aggregate compacts by ~23% when laid; ordering 30% extra ensures the required depth.
How does this calculator work?
Volume to order = L × W × depth × 1.30 (compaction factor), in cubic metres. Weight = compacted volume × bulk density (default 1800 kg/m³). For a 10 m × 3 m driveway at 150 mm deep: 4.5 m³ compacted, order ~5.85 m³ (≈ 8.1 tonnes). Always confirm density and compaction factor with your supplier.
Formula
How this is calculated
Road base (also sold as crusher run, compacted gravel, DGA, road mix, or sub-base aggregate) is a granular material used as a structural foundation layer under driveways, paths, patios and roads. Calculating the required quantity has two steps: first, work out the compacted volume from the plan area and design depth (typically 100–150 mm for residential driveways and 150–300 mm for heavier traffic); second, apply a compaction (bulking) factor because the aggregate arrives loose and compacts down by roughly 20–25% when properly laid and compacted.
The compaction factor of 1.30 used here is a conservative rule of thumb — it means you order 30% more loose material than the compacted volume you need. Actual compaction ratios vary from about 1.20 to 1.35 depending on the gradation of the aggregate, moisture content and compaction equipment. Always confirm with your supplier; most aggregate suppliers can advise the specific factor for their product.
The bulk density field (default 1800 kg/m³, 2026 estimate) converts volume to mass for ordering by the tonne. Typical compacted road base runs 1700–2000 kg/m³. Crushed limestone tends toward 1800–1950, granite aggregate toward 1750–1900, and recycled concrete aggregate toward 1600–1750. Edit the density to match your supplier's specification.
Frequently asked questions
Quarried aggregate is loaded and transported loose — it has air voids. When laid and compacted by a plate compactor or roller, those voids close and the material shrinks in volume by roughly 20–25%. The compaction (bulking) factor of 1.30 means you order 30% more than the finished compacted volume, providing a small buffer. Your supplier will usually state their product's specific factor.
For a residential driveway with light vehicles, 100–150 mm of compacted road base is typical. For driveways with heavier vehicles (vans, trucks) or poor sub-grade soil, 150–200 mm or more may be needed. Paths and patios can use 75–100 mm. Always compact in lifts no thicker than 100–150 mm per pass for good density.
Yes — change the bulk density to match your material. Clean gravel: ~1500 kg/m³; coarse sand: ~1600 kg/m³; fine sand: ~1700 kg/m³; concrete: ~2400 kg/m³ (but concrete volume is not normally adjusted for compaction). The compaction factor of 1.30 is specific to granular aggregate; for concrete, remove it by setting the volume order equal to the compacted volume.
Also known as
TG we-Calculate Editorial Team. (2026). Road Base Calculator — Volume & Tonnes of Aggregate [Online calculator]. TG we-Calculate. https://we-calculate.com/calculator/road-base-calculator
TG we-Calculate Editorial Team. "Road Base Calculator — Volume & Tonnes of Aggregate." TG we-Calculate. 2026. https://we-calculate.com/calculator/road-base-calculator.
TG we-Calculate Editorial Team, "Road Base Calculator — Volume & Tonnes of Aggregate," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/calculator/road-base-calculator
@misc{wecalculate_road_base_calculator, title = {Road Base Calculator — Volume & Tonnes of Aggregate}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/calculator/road-base-calculator}}, year = {2026}, note = {TG we-Calculate} }
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