How Much Gravel for a 20x80 Driveway?

How much gravel for a 20x80 driveway is a quick volume problem. 1,600 square feet at 4 inches comes to 19.75 cubic yards. Gravel usually weighs about 1.3 to 1.5 tons per cubic yard, so plan on roughly 27.7 tons.

Volume and tonnage calculator →

The math for a 20x80 driveway

Area: 20 × 80 = 1,600 sq ft.
Depth in feet: 4 ÷ 12 = 0.333 ft.
Cubic feet: 1,600 × 0.333 = 533.3 cu ft.
Cubic yards: ÷ 27 = 19.75 yd³.
Tons: × 1.4 = 27.7 tons.

The volume and tonnage calculator does this for any size.

Gravel needed by depth

Depth	Cubic yards	Tons (approx.)	Tons +10%
2 in	9.88	13.8	15.2
3 in	14.81	20.7	22.8
4 in	19.75	27.7	30.4
6 in	29.63	41.5	45.6

About gravel

Plain gravel is a loose term. Yards use it for rounded bank or river stone as well as for crushed rock, so ask whether the load is washed, crushed or a mix before you lock in a tonnage. Ask your supplier for their own tons-per-yard figure, since stone source and moisture shift it.

Preparing the driveway

Strip sod and soft topsoil, grade for drainage and compact the subgrade before any stone goes down. Gravel drives last longer with a compacted base layer under the top stone and a slight crown so water runs off. Since the driveway carries car and truck traffic, a little extra depth is cheap insurance.

Ordering tips

Round up. Compaction and uneven ground eat material. Adding about 10 percent is common.
Delivery size. 30.4 tons may take more than one typical dump truck load; small loads may carry a delivery fee. See how many tons of gravel in a dump truck.
Bulk vs bags. At this size bulk delivery is usually the practical choice.
Where it drops. Have the truck dump as close to the driveway as firm ground allows.

Good and poor uses for gravel

Best suited to:

Rural driveways and lanes where low upfront cost matters
Drainage areas and around downspouts
Temporary access while a site is under construction

Less suited to:

Steep slopes, where loose stone washes downhill
Spots plowed often, since plows push gravel into the lawn
Areas next to doors, because stone tracks inside

Quick reference numbers

Per inch over 100 sq ft: about 0.43 tons of gravel (0.31 cubic yards).
Per inch over 1,000 sq ft: about 4.3 tons.
Another size for comparison: a 14x28 area at 2 inches takes about 3.4 tons.
Weight used here: about 1.4 tons per cubic yard.

Where estimates go wrong

Mixing up cubic yards and tons. Yards are volume, tons are weight; convert with the product’s weight per yard.
Using inches as if they were feet. Depth has to be divided by 12 before you multiply; skipping that step inflates the order twelvefold.
Measuring only the main rectangle. Aprons, turnouts and curved edges add real square footage.
Ordering exactly the math. Uneven ground and spillage nearly always need a little more than the flat calculation.

Questions people ask

How many tons of gravel for a 20x80 driveway?

About 27.7 tons at 4 inches deep, or 30.4 tons with 10 percent extra.

How many cubic yards is a 20x80 driveway at 4 inches?

About 19.75 cubic yards.

How much does a cubic yard of gravel weigh?

Usually around 1.3 to 1.5 tons, depending on stone size, fines and moisture.

How deep should gravel be for a driveway?

The table above shows 2 to 6 inches. Shallower depths suit top dressing; deeper depths suit new installs and heavier use.

How many square feet is 20x80?

1,600 square feet.

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