Pea Gravel Calculator

How to calculate pea gravel

Pea gravel is measured like any gravel: area times depth gives volume, and volume times weight per yard gives tons.

Cubic yards = length (ft) × width (ft) × depth (in) ÷ 324
Tons = cubic yards × 1.4 · Bags (0.5 ft³) = cubic feet ÷ 0.5

The calculator above runs the same math and returns cubic yards, cubic feet, cubic meters, tons, tonnes and the number of 0.5 ft³ bags.

1. Measure the area in feet. Split curved beds or L-shaped paths into rectangles and add them.
2. Pick a depth. Pea gravel is round, so it does not lock together like crushed stone. A thin layer stays put better.
3. Add 10% for settling and spillage.
4. Choose bags or bulk. One cubic yard is 54 bags of 0.5 ft³.

How much pea gravel for common sizes?

The table gives pea gravel at 2 in and 3 in deep, the usual range for patios and paths. Figures come from the site’s calculation library at 1.4 tons per yd³.

Add 10% to whichever column you use. A 3 × 30 ft path at 3 in deep needs 0.83 yd³ (1.17 tons, 45 bags), or 1.28 tons ordered.

How deep should pea gravel be?

Depth depends on use. Pea gravel rolls, so going deeper than needed makes it harder to walk on, not stronger.

These depths are common practice, not a rule. Lay pea gravel over a compacted base and landscape fabric, and use edging (steel, timber or pavers) so the stones do not migrate into the lawn.

Playgrounds: loose-fill depth under play equipment depends on fall height and is set by safety guidance such as the US Consumer Product Safety Commission’s playground handbook. Check that guidance for your equipment, then enter the depth here. For example, a 20 × 20 ft area at 9 in deep needs 11.11 yd³, about 15.56 tons.

Because playground depths are several times a patio depth, it helps to plan per 100 ft²: 1.85 yd³ (2.59 tons) at 6 in, 2.78 yd³ (3.89 tons) at 9 in and 3.7 yd³ (5.19 tons) at 12 in. Loose fill gets kicked out from under swings and slide exits, so measure those spots again after a few weeks of use and top them back up to the depth you planned. Containment edging taller than the fill depth keeps the stone where it is needed.

How much does pea gravel weigh?

A cubic yard of pea gravel weighs about 1.4 tons, or 2,800 lb, which is about 104 lb per cubic foot. At that planning density a 0.5 ft³ bag would hold about 52 lb; the bag label gives the actual weight. Wet pea gravel weighs more. The 1.4 figure is a planning value, so if your supplier sells by the ton and quotes its own weight per yard, use theirs.

Pea gravel per square metre

In metric, the same 1.4 tons per yd³ planning density works out at about 1.66 tonnes per m³ of pea gravel; use your supplier’s figure if it differs.

A 50 mm layer, close to 2 in, needs about 83 kg per square metre, so one tonne covers about 12 m². At 40 mm, a common depth for a garden path, it is about 66 kg per m² or 15 m² per tonne. Worked in metres: a 4 × 3 m seating area at 50 mm is 4 × 3 × 0.05 = 0.6 m³, about 1 tonne, or 1.1 tonnes with 10% extra. A 10 m path 1 m wide at 50 mm is 0.5 m³, about 0.83 tonnes.

How much pea gravel for a path or walkway?

Paths are long and narrow, so it is easier to work per 10 ft of length. Multiply the row for your width and depth by your path length ÷ 10.

A 4 × 50 ft path at 2 in deep is 200 ft², which needs 1.23 yd³, about 1.73 tons or 67 bags; with 10% extra order 1.9 tons. At 3 in it rises to 1.85 yd³ and 2.59 tons. Most garden paths of pea gravel work well at 2 in; go to 3 in only over a firm, compacted base.

Paths with stepping stones

Subtract the stones before you calculate. Fifteen 18 × 18 in stepping stones cover 15 × 1.5 × 1.5 = 33.75 ft². On a 3 × 30 ft path (90 ft²) that leaves 56.3 ft² of gravel. At 2 in deep that is 0.35 yd³, about 0.49 tons or 19 bags (21 with 10% extra), against 30 bags for the same path without stones. Set the stones first, then spread the gravel level with their tops or slightly below.

How much pea gravel for a fire pit area or round patio?

Round areas are popular for fire pits and seating. Choose Circle in the calculator and enter the diameter, or use the table:

Bags are 0.5 ft³ and the figures are before the 10% extra. For a ring around a fire pit, subtract the pit itself: a 16 ft circle with a 4 ft pit leaves 188.5 ft², which at 3 in is 1.75 yd³, about 2.44 tons or 95 bags, and 2.69 tons with 10% extra. Keep a non-combustible border between the pit and any seating, and follow the fire pit maker’s clearance guidance.

Pea gravel for a dog run: common sizes

Dog runs get dug, kicked and hosed, so they are commonly laid at 3–4 in rather than the 2 in used on a path. These sizes use 1.4 tons per yd³ and include the 10% extra in the last two columns.

A small 4 × 10 ft kennel run at 3 in takes 20 bags of 0.5 ft³, which is manageable by car. A 20 × 30 ft yard run at 4 in is 400 bags, so price a bulk delivery. Rinse-off and drainage matter more than depth here: lay the stone over a free-draining base so urine and hose water do not pool under it.

What goes under pea gravel?

Pea gravel works best as a top layer over something that does not move. On firm, well-drained ground, compacted soil and landscape fabric are often enough. On soft or wet ground, put down a compacted layer of angular crushed stone first, sized with the gravel calculator.

The base adds real tonnage, so count it in your order. For a 12 × 12 ft patio with 3 in of #57 crushed stone under 2 in of pea gravel, the base is 1.33 yd³ (about 1.8 tons at a typical planning weight of 1.35 tons per yd³ for #57 stone; use your supplier’s figure) and the pea gravel 0.89 yd³ (1.24 tons): about 3 tons of stone before the extra, and two separate products on the delivery ticket. For a 10 × 20 ft area with a 4 in crushed stone base and 3 in of pea gravel, the figures are 3.33 tons of base and 2.59 tons of pea gravel.

Plastic or honeycomb gravel stabilizer grids are another way to stop pea gravel shifting on patios and light-use parking. If you use one, fill it to the depth the manufacturer states and enter that depth here.

A pea gravel border around a patio

A border is the outer rectangle minus the patio. A 2 ft band around a 12 × 12 ft patio is 16 × 16 − 12 × 12 = 112 ft². At 3 in deep that is 1.04 yd³, about 1.45 tons or 56 bags, and 1.6 tons with 10% extra.

How much pea gravel to top up an existing area?

Order only the missing depth, not the full depth. Push a ruler down through the gravel to the fabric or base at five or six spots, average the readings, and subtract from your target depth. That difference is the depth to enter in the calculator.

For a 12 × 12 ft patio that has thinned from 2 in to about 1 in, the top-up is 1 in deep: 0.44 yd³, about 0.62 tons or 24 bags of 0.5 ft³, and 0.68 tons with 10% extra. For a 4 × 50 ft path short by 1 in, it is 0.62 yd³, about 0.86 tons or 34 bags. Rake the old stone level before measuring, because stones pushed to the edges make the middle read thin.

Pea gravel or crushed stone for a patio?

At the site’s planning weights (1.4 and 1.35 tons per yd³) the tonnage hardly changes: a 12 × 12 ft patio at 3 in needs about 1.87 tons of pea gravel or 1.8 tons of #57 crushed stone. Your supplier’s weights may differ. The difference is how they behave underfoot.

• Choose pea gravel for seating areas, paths and play spaces where comfort and a soft look matter, with edging on every side and a commonly used depth of 2–3 in.
• Choose crushed stone or crusher run where chairs, tables, wheelbarrows or a grill must stand level, or where the surface slopes. The angular pieces lock together; round pea gravel keeps rolling.
• Combine them by using crushed stone as the compacted base and a thin pea gravel top, as in the base example above.

Pea gravel is not a good driving surface. For a parking area or drive, use the driveway gravel calculator, which works in layers of angular stone.

Common mistakes when laying pea gravel

Pea gravel is forgiving to spread but easy to over-order or under-support. These mistakes come up most often:

• Spreading it too deep. More than about 3 in on a patio feels like walking on marbles. A 10 × 10 ft area at 4 in takes 1.73 tons against 0.86 tons at 2 in, double the stone for a worse surface.
• Ordering tons when you worked out yards. At 1.4 tons per yd³, ordering the yard figure in tons leaves you about 29% short.
• Skipping the edging. Round stones migrate into lawns and beds within a season without a border.
• No base or fabric. Pea gravel laid on bare soil sinks and mixes with dirt. Compact the ground and lay landscape fabric first.
• Forgetting the extra. Order about 10% more than the exact volume to cover settling and low spots: on a 12 × 12 ft patio at 3 in, that is 1.87 tons exact and about 2.05 tons ordered.
• Buying bags for a big area. A 500 ft² area at 3 in is 250 bags of 0.5 ft³, about 6.48 tons to carry by hand. Price bulk delivery first.

Bags or bulk pea gravel?

Bags are practical up to about half a cubic yard (27 bags of 0.5 ft³). Above that, bulk delivery is usually less work, since a 10 × 20 ft patio at 3 in takes 100 bags. Delivery fees and minimums vary, so ask local landscape yards for a quote by the ton or yard, and compare with the tons to cubic yards converter.

Not every store sells 0.5 ft³ bags. Count from the volume on the label; the last column shows a 12 × 12 ft patio at 3 in (36 ft³) for each size.

If the bag gives only a weight, divide the job’s pounds by it: the 12 × 12 ft patio at 3 in is about 3,730 lb of pea gravel.

Pea gravel calculator vs gravel, river rock and mulch calculators: which one to use

Use this pea gravel calculator for patios, paths, dog runs and play areas surfaced with small round stone. For other jobs:

• Gravel calculator: compacted bases for sheds, slabs and drains, with presets for #57 crushed stone and crusher run, which lock together where pea gravel does not.
• River rock calculator: larger decorative stone in beds and dry creeks, where depth follows stone size.
• Mulch calculator: planted beds next to the gravel, sold by the cubic yard or in bags.
• Tons to cubic yards: converting a price per ton into a price per yard before you compare quotes.