About the Pea Gravel Calculator
This pea gravel calculator works out how much you need and which way of buying it is cheaper. Enter the size and depth of the area, the price of a 0.5 cubic foot bag, the bulk price per ton and the delivery fee. It gives the cubic yards and tons, the number of bags and their cost, the bulk cost including delivery, and the volume above which bulk becomes the better deal.
How to Use the Pea Gravel Calculator
Enter the length and width of the area in feet and the depth in inches.
Enter an extra for spreading allowance, usually 5%.
Enter the price per bag, the bulk price per ton and the delivery fee.
The Formulas
cubic feet = length × width × depth ÷ 12 × (1 + extra)
cubic yards = cubic feet ÷ 27
tons = cubic yards × 1.3
bags = ⌈cubic feet ÷ 0.5⌉
bag cost = bags × bag price
bulk cost = tons × price per ton + deliveryStep-by-Step Example
A 10 × 10 ft patio, 3 inches deep, with $6 bags, $45 a ton bulk and $75 delivery.
volume 10 × 10 × 3 ÷ 12 = 25 ft³ × 1.05 = 26.25 ft³
yards 26.25 ÷ 27 = 0.97 yd³ = 1.26 tons
bags 26.25 ÷ 0.5 = 53 bags × $6 = $318
bulk 1.26 × $45 + $75 = $131.88
verdict bulk is cheaperBags or Bulk?
Bagged pea gravel costs far more per cubic foot. At $6 for half a cubic foot you pay $12 a cubic foot, while $45 a ton works out at a little over $2. The delivery fee is what keeps bags competitive for small jobs. In the example, the price gap of nearly $10 a cubic foot covers the $75 delivery once you need about 8 cubic feet, roughly 16 bags. Below that, a few bags in the car are simpler; above it, bulk wins quickly. Bags still have uses: they are clean, easy to store and handy for topping up a path each spring or reaching a back garden with no access for a truck.
Choosing the Depth
The right depth depends on the use. Paths and patios need about 2 to 3 inches over a compacted base; much more and the surface becomes soft and hard to walk on. Under play equipment, safety guidance calls for at least 9 inches of loose fill, and 12 inches for higher equipment, because the gravel must cushion falls. It is pushed aside by use, so it needs raking back and topping up regularly. Dog runs usually use 3 to 4 inches over a free-draining base so urine drains away and the area can be hosed down.
Preparing the Ground
Dig out the area to the depth of the gravel plus any base, remove roots and level the soil. For a patio, lay and compact 3 to 4 inches of crushed stone such as #57 or crusher run, which gives a firm platform the round pea gravel cannot provide on its own. Lay landscape fabric to block weeds, then spread the pea gravel and rake it level. Pea gravel stabiliser grids, honeycomb panels filled with gravel, stop it shifting under chairs and make paths firmer for wheelchairs and pushchairs.
Keeping Pea Gravel in Place
Rounded stones roll, so pea gravel spreads into lawns and beds unless it is held by edging. Steel, aluminium, treated timber, brick or stone edging set an inch or so above the gravel surface keeps it contained. Where a path meets a door, a hard landing such as a paver stops stones being carried indoors on shoes.
Weight and Handling
A 0.5 cubic foot bag of pea gravel weighs about 45 to 50 pounds, and a cubic yard about 1.3 tons. A wheelbarrow holds around 2 to 3 cubic feet, so a cubic yard is roughly ten loads. Plan where the delivery will be tipped, ideally on a tarp close to the work, and ask the driver to avoid soft lawns and septic tanks.
Pea Gravel Colours and Sources
Pea gravel is dug from river and glacial deposits rather than crushed from bedrock, which is why it is smooth and rounded. Its colour depends on where it comes from: buff, tan and grey mixes are common, while some yards stock white, pink or black varieties at a higher price. Colours look richer when wet, so view a sample after rain or hose it down before deciding. Because each pit produces slightly different stone, order enough for the whole project in one go, so a later top-up does not look patchy against the original.
Drainage Uses
The gaps between rounded stones let water pass quickly, so pea gravel is also used around downspouts, as a backfill around drainage pipes and as a soakaway surface. For a French drain or behind a retaining wall, though, angular clean stone such as #57 is usually preferred because it locks in place and does not shift as soil settles around it.
Understanding Your Result
The headline gives the cubic yards and tons of pea gravel.
The bagged line shows the number of bags and their cost.
The bulk line shows the tons, price and delivery.
The cheaper option line names the better buy and the break-even volume.
When Should You Use This Calculator?
Use it when planning a pea gravel patio, path or play area.
Use it to decide between a trip to the store and a delivery.
Use it to budget the yearly top-up for a play area.
Common Mistakes
Laying pea gravel too deep for walking. Keep paths to 2 or 3 inches.
Skipping edging. The stones migrate without it.
Forgetting delivery in the bulk price. Small loads can cost more than bags.
Spreading straight onto soil. A compacted base and fabric keep it firm and clean.