Stone Calculator

Measure the area and depth; get the yards and tons of stone.

Sources checked 9 November 2026

Rectangle 16′ 0″ × 12′ 0″, 6″ deep, crushed rock, top course, 10% extra

Fig. 1 The example rectangle, drawn to scale at its depth. Top area 192 sq ft. The circle shows the depth at about 3× size. The circle shows the depth at about 4× size.

Example: rectangle 16′ 0″ × 12′ 0″, 6″ deep. Type your sizes

3.91cubic yardswith 10% extra

Before the extra: 96.00 cu ft = 3.56 cu yd

Bulk: 3.91 4.0; cu yd, in half yards
Weight: 5.6; tons of crushed rock, top course

Your own sizes need scripts turned on. Without them the page shows the worked example.

Filled in with an example. Type your sizes over it.

Stone

Sets the tons. Crushed rock and ballast as hauled from WSDOT; trap rock and gravel from FM 5-434. River rock and pea gravel are rounded gravel: pick Gravel.

Length

Width

Depth

Unilock: base under a paver patio or walk 6 to 8 in; Unilock: base, diy guide: walkways; driveways 4 to 6 in; 8 to 12 in.

Extra to order

A landscape supplier’s rule: 5 to 10% for gravel. A base you compact needs more: a loose yard of gravel packs down to 0.86 yd (FM 5-434).

To order

Rectangle 16′ 0″ × 12′ 0″, 6″ deep: 3.91 cu yd with 10% extra. Order by the yard or by the ton.

Item	Count	Note
Volume	3.56 cu yd	96.00 cu ft, before the extra.
Extra	+0.36 cu yd	10% on its own line.
Bulk	3.91 4.0 cu yd	With 10% extra, rounded up to the next half yard.
Weight	5.6 tons	crushed rock, top course at 2,850 lb a cubic yard, loose.

How much stone do I need

Multiply the length, width and depth in feet, divide by 27 for cubic yards, add the extra, and multiply by the tons in a yard of your stone. A 12 × 16 ft patio base, 6 in deep is 96 cubic feet, or 3.56 cubic yards; with 10% extra, 3.91 cubic yards or 5.6 tons of crushed rock, top course.

Pick the stone to set the tons. Crushed rock as hauled weighs 2,850 lb a yard, so a yard is 1.43 tons and a ton is 0.70 cubic yards.

Read the tape into feet
16′ 0″ = 16 ft. 12′ 0″ = 12 ft. 6″ = 6 ÷ 12 = 0.500 ft.
Area times depth for each piece
- 16.00 × 12.00 = 192.00 sq ft; × 0.500 ft deep = 96.00 cu ft
Divide by 27 for cubic yards
96.00 ÷ 27 = 3.56 cu yd
Add the extra
3.56 × 1.10 = 3.91 cu yd. That is the number to order.
Weight: yards × pounds per yard ÷ 2,000
3.91 × 2,850 ÷ 2,000 = 5.6 tons of crushed rock, top course

Cubic yards = length × width × depth ÷ 27 × (1 + extra)

16.00 × 12.00 × 0.500 = 96.00 cu ft; ÷ 27 = 3.56 cu yd; × 1.10 = 3.91 cu yd

All sizes in feet.

Crushed stone, river rock and landscape rock

Crushed stone has broken faces that lock together, so it packs into a firm base for a patio, a shed pad or a driveway. River rock and pea gravel are rounded: they stay loose, so they suit paths, beds and drainage. We found no published weight under the names river rock or decorative stone; they are rounded gravel, so pick Gravel in the calculator.

Weight of a cubic yard, loose
Material	Pounds per cu yd	Tons per cu yd	Cu yd per ton
Crushed rock, top course	2,850	1.43	0.70
Crushed rock, base course	2,950	1.48	0.68
Ballast	3,100	1.55	0.65
Trap rock	2,700 to 3,500	1.35 to 1.75	0.57 to 0.74
Gravel, dry	2,700 to 3,000	1.35 to 1.50	0.67 to 0.74
Gravel, wet	2,800 to 3,100	1.40 to 1.55	0.65 to 0.71

Loose weights as hauled, from WSDOT Design Manual M 22-01.23 and U.S. Army FM 5-434. Tons per yard: pounds ÷ 2,000; yards per ton: 2,000 ÷ pounds. Wet material is heavier.

Crushed stone calculator formula

Cubic yards = length × width × depth, all in feet, ÷ 27. Divide by 27 to convert cubic feet into cubic yards, because 1 cubic yard is 27 cubic feet; depth in inches ÷ 12 gives feet. Tons = cubic yards × pounds per cubic yard ÷ 2,000.

Stone weight calculator: how many cubic yards are in a ton

How many cubic yards are in a ton depends on the stone. A cubic yard of crushed rock, top course, weighs 2,850 lb, so a ton is 0.70 cubic yards. Base course weighs 2,950 lb and railroad ballast 3,100 lb a cubic yard. Pick the stone in the calculator and it works out the stone weight with the yards.

To calculate the weight of any stone by hand, multiply the cubic yards by the pounds in a cubic yard of that material. Gravel weighs less than crushed rock: dry gravel weighs 2,700 to 3,000 lb a cubic yard and wet gravel 2,800 to 3,100 lb. For pea gravel and driveways, the gravel calculator uses the same weights.

Stone in tons by area and depth

Tons of crushed rock, no extra added. For a base you compact, add the extra: a loose yard of rock or gravel packs down to about 0.86 cubic yards.

Tons of crushed rock, top course by area and depth
Area	2 in deep	3 in deep	4 in deep	6 in deep
100 sq ft	0.9	1.3	1.8	2.6
200 sq ft	1.8	2.6	3.5	5.3
500 sq ft	4.4	6.6	8.8	13.2
1,000 sq ft	8.8	13.2	17.6	26.4

Tons of crushed rock, top course at 2,850 lb a cubic yard: area × depth ÷ 27 for yards, then × pounds ÷ 2,000. No extra added.

Square feet one ton covers
Depth	Sq ft per ton
2 in	114
3 in	76
4 in	57
6 in	38

Crushed rock, top course: yards in a ton × 27 ÷ (depth in inches ÷ 12).

How deep to spread it
Job	Depth	Who says so
Gravel driveway apron, first 10 ft from the road	6 in aggregate base under 3 in asphalt; 9 in behind it	Franklin County (OH) Engineer
Base under a paver patio or walk	6 to 8 in	Unilock
Base under a paver driveway	10 to 14 in	Unilock
Base, DIY guide: walkways; driveways	4 to 6 in; 8 to 12 in	Unilock
Pea gravel under a playground	9 in at least	U.S. CPSC

From each guide as written: Franklin County (OH) Engineer, Unilock, U.S. Consumer Product Safety Commission.