Crushed Rock Calculator
Estimate crushed rock volume and tonnage for driveway and slab sub-base preparation.
Crushed Rock Calculator
Estimate crushed rock volume and tonnage for driveway and slab sub-base.
Estimating Crushed Rock For Sub-Base Preparation
Crushed rock is used beneath driveways and slabs to create a stable, well-draining base that reduces movement in the concrete above. Volume is calculated as area (m²) × depth (m), converted to tonnage using a typical compacted crushed rock density of 1.65 tonnes per cubic metre.
What Information You Need To Enter
Enter your project area in square metres and base depth in millimetres (100 mm is a common driveway sub-base depth).
Understanding Your Results
You will see the crushed rock volume required and approximate tonnage. This is the same base allowance used in our Concrete Driveway Calculator, so the two are consistent if you are estimating a full driveway project.
Why Accurate Estimating Matters
A properly prepared sub-base is one of the most important factors in how well a driveway or slab performs over time, so an accurate crushed rock estimate helps you budget and order the right quantity for solid, long-lasting base preparation.
Frequently Asked Questions
How deep should a crushed rock base be under a driveway?
A common depth is around 100 mm, though this can increase on softer or more reactive soils. Your concreter or engineer can confirm the right depth for your site conditions.
Why is a crushed rock base important?
A well-compacted crushed rock base provides a stable, even surface for concrete to be poured on, improves drainage, and reduces the risk of the slab cracking or settling unevenly over time.
Is this the same as road base?
"Road base" is a common term for a compactable crushed rock product suited to driveways and light-traffic pavement sub-base, and this calculator's density figure reflects typical compacted road base material.
Does this calculator match the driveway calculator?
Yes -- this uses the same crushed rock allowance as our Concrete Driveway Calculator, so you can use either depending on whether you want a full driveway materials list or a rock-only estimate.
Can crushed rock be used for drainage as well as base preparation?
Yes, crushed rock (sometimes a different grade) is also commonly used for drainage behind retaining walls -- see our Concrete Sleeper or Timber Sleeper Retaining Wall calculators for drainage-specific quantities.
Related Calculators & Services
Need An Exact Price, Not Just An Estimate?
The Crushed Rock Calculator gives you a fast, useful planning figure. For a fixed, accurate price backed by a site assessment, request a free professional quotation from HPL Construction.
