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Decomposed Granite Calculator

Calculate the tons of decomposed granite for paths and patios.

ft
ft
in
Pathways need 2–3 in. Patios and driveways need 4 in over a compacted base.
Decomposed granite needed — tons
Volume — cu yd
Order allowing 25% compaction — tons

What you'll need to order

Prices vary by region and haul distance. Get quotes from at least two local suppliers.

How this calculator works

tons = length × width × (depth ÷ 12) × 110 ÷ 2000

Decomposed granite weighs about 110 lb per cubic foot once compacted, and loses roughly a quarter of its loose volume when rolled. The headline figure is compacted depth; the order figure adds that 25% back.

Switch the site to metric — the control is in the footer — and your inputs, your results and the tables below follow. The formula, the constants, the guidance text and the sources stay in US units on purpose: that is how the standards they come from are written, and restating them would detach each figure from the document you are meant to be able to check it against.

Where these numbers come from

Cited to a specific edition on purpose — table numbers and values move between cycles. Confirm against whichever edition is enforced locally.

Worked example

With length 10 ft, width 10 ft, compacted depth 3 in, this calculator returns 1.38 tons.

Waste allowance

The headline figure includes a 25% allowance for waste and over-ordering. The exact requirement is shown alongside it.

Decomposed granite for common paths and patios

Each row is a link that fills in the calculator above. Send one and the other end sees the same figures you do.

JobSizeDecomposed granite needed
Garden path 40 ft × 3 ft × 3 in 1.65 tons
Wide walkway 60 ft × 4 ft × 3 in 3.30 tons
Patio 20 ft × 16 ft × 3 in 4.40 tons
Driveway topping 60 ft × 12 ft × 4 in 13.20 tons
Dog run 30 ft × 10 ft × 2 in 2.75 tons

Order to compacted depth. DG loses roughly a quarter of its loose volume once rolled.

Frequently asked questions

How much decomposed granite do I need?

Multiply area by depth in feet, then by 110 and divide by 2,000 for compacted tons. A 40 by 4 ft path at 3 inches deep needs 2.2 tons compacted, so order about 2.75 tons loose.

Does decomposed granite need a binder?

For a firm, low-maintenance surface, yes. Stabilised DG mixed with a binder resists erosion and tracking. Plain DG is cheaper but washes out on slopes and gets carried indoors on shoes.

How deep should decomposed granite be?

Two to three inches compacted for a pathway, and four inches over a compacted base for patios or vehicle traffic. Deeper than that stays soft and rutted underfoot.

Is decomposed granite good for a driveway?

Only with a stabiliser and a proper compacted base beneath it. Unstabilised DG rutted by tyres needs regular regrading, whereas a stabilised installation over road base holds up for years.

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