Blue Metal Calculator
Work out how much blue metal (crushed rock gravel) you need. Enter the area, the calculator returns cubic metres for a typical depth, plus an indicative cost, useful for driveways, drainage and under-slab fill.
How we estimate this
Blue metal is crushed rock sold by the cubic metre or tonne. At a 75mm layer, one cubic metre covers about 13 square metres, so a 30m² area needs roughly 2.3 cubic metres. Driveway bases and drainage trenches are often deeper.
Pricing reviewed: November 2026.
Pricing reviewed November 2026. Indicative Australian costs, not a quote.
Understanding blue metals in Australia
Blue metal is crushed rock sold by the cubic metre or tonne. At a 75mm layer, one cubic metre covers about 13 square metres, so a 30m² area needs roughly 2.3 cubic metres. Driveway bases and drainage trenches are often deeper.
Choose the right size for the job, smaller aggregate for drainage and under slabs, larger for a driveway base. Bulk delivery is far cheaper per cubic metre than bags for anything beyond a small quantity.
Frequently asked questions
How much blue metal do I need?
At a 75mm layer, one cubic metre covers about 13 square metres, so a 30m² area needs roughly 2.3 cubic metres. Driveway bases are usually deeper. Enter your area for an estimate.
What size blue metal should I use?
Smaller aggregate (7 to 14mm) for drainage and under slabs, larger (20mm+) for a driveway base. Confirm the size with your supplier for the specific job.
Are you a quarry / landscape supply?
Everyone on this page is working out what blue metal costs because they are ready to hire. Put your business right beneath the calculator, in your state, so you are who they find. From $50/mo.