Pea Gravel Calculator
Path, patio, or playset: pea gravel yardage in seconds
What is pea gravel calculator?
A pea gravel calculator answers the homeowner’s first question on any path, patio, or playset project: how many bags or cubic yards do I need. The volume math (length times width times depth) is straightforward; pea gravel at retailers comes in 50-lb bags covering roughly 0.5 cubic feet, and bulk from landscape suppliers is priced by the ton.
The default density is 100 lb/ft³ for typical river-rounded pea gravel. The smooth, round shape leaves more air space between stones than angular crushed stone, which is why pea gravel is at the lighter end of decorative gravels. Volume math doesn’t change with stone type; only the weight readout does.
What depth to choose? Two to three inches works for paths and walkways over a weed barrier — anything thinner and the fabric shows through. Four to six inches is common for casual backyard playset substrate. For an ASTM-rated drop zone (what public playgrounds use), nine to twelve inches loose is the minimum, and engineered wood fiber is often a better choice.
Bulk vs bagged: at the home center, a 50-lb bag of pea gravel runs $5-9 and covers about 0.5 cubic feet. A cubic yard equals about 54 bags. Past 1 yard, bulk delivery wins on price; below that, bags are easier and you skip the delivery wait.
The 10% waste factor default covers spread loss and edge spill. Bump to 15% for paths with curves or unedged borders — pea gravel migrates outward under foot traffic and slides downhill on any slope. Plan on topping off annually if your path is unedged or transits a slope.
Pea gravel needs a retaining edge — steel, stone, or wood-plank borders are essential because round stones roll. Without edging, your path widens and thins every season, and you’ll be ordering more pea gravel every spring.
When to use a pea gravel calculator
- Playset substrate — ASTM-spec playground surfacing calls for 9-12 inches of loose pea gravel. Most homeowners use 4-6 inches for casual backyard sets.
- Garden path or walkway — 2-3 inches of pea gravel over a weed barrier creates a low-budget path. The calculator outputs both yards and 50-lb bag count.
- Drainage aggregate — Pea gravel under a French drain or downspout splash zone. Round stones drain faster than angular crushed stone.
How to use the Pea Gravel Calculator
- Measure the area — For paths and patios, multiply length by width. For round play areas, the calculator takes diameter directly. For winding paths, multiply average width by total length.
- Pick a depth — 2-3 inches for paths and walkways (over weed barrier). 4-6 inches for casual playset substrate. 9-12 inches for ASTM-rated playground drop zones.
- Read the bag count — Output shows 50-lb bags (the home-center standard for pea gravel). Each bag covers about 0.5 cubic feet. Round up — partial bags are awkward to store outdoors.
- Apply waste factor — 10% covers spread loss and edge spill. Bump to 15% for paths with curves or borders that aren't fully edged — pea gravel migrates outward over time without retainers.
Worked examples
Garden path, 3 ft x 50 ft at 3 in
Input: 3 ft x 50 ft x 3 in depth
Output: 1.39 cu yd / 75 of 50-lb bags (with 10% waste)Backyard playset pad
Input: 12 ft x 12 ft x 6 in depth
Output: 2.67 cu yd / 144 of 50-lb bagsFor an ASTM-rated drop zone, go 9 in minimum and use engineered wood fiber instead.
Splash zone under downspout
Input: 3 ft x 4 ft x 4 in depth
Output: 0.16 cu yd / 9 of 50-lb bags