ImperialCalcs US Imperial

Bulk Aggregates & Landscaping

Pea Gravel for a 16x20 ft Project at 4 Inches Deep

For pea gravel at 16 × 20 ft at 4 in, the estimate includes 10% waste. Allow 4.35 cubic yards (117.33 cubic feet), or 235 bags at 0.5 cu ft each.

01 / Project measurements

Shape
Length
Width
Depth / thickness

02 / Ordering allowance

Waste factor

10% recommended · 15% for irregular projects

Geometry previewISO / 01
L 16 ftW 20 ftD 4 in

Live material estimate

Rectangle 16 × 20 ft × 4″ deep · 10% waste

Total cubic yards

4.346 yd³

117.33 ft³ · 320 ft²

Estimated weight

5.541 US short tons

11,081.5 lb · 2,000 lb per ton

Store bag alternatives

235 × 0.5 cu ft bags$1,287.80
294 × 0.4 cu ft bags$1,317.12

Bulk or bags?

Bulk with delivery$335.55

Lowest bag total$1,287.80

Bulk delivery saves $952.25.

Planning price $38.00 per short ton. Confirm local rates and minimums.

ImperialCalcs · Contractor field tools

Material Estimate

Pea Gravel

Rectangle 16 × 20 ft × 4″ deep · 10% waste

ItemQuantityUnit rateAmount
Pea Gravel (bulk)5.541 ton$38.00$210.55
Delivery1 trip$125.00$125.00
Materials
$335.55
Estimate total
$335.55

Quick reference

Pea Gravel order quantities with 10% waste
FootprintDepthCubic yardsShort tons0.5 cu ft bags
8 × 10 ft4 in1.091.3959
8 × 10 ft6 in1.632.0888
10 × 10 ft4 in1.361.7374
10 × 10 ft6 in2.042.6110
12 × 16 ft4 in2.613.32141
12 × 16 ft6 in3.914.99212
16 × 20 ft4 in4.355.54235
16 × 20 ft6 in6.528.31352
20 × 20 ft4 in5.436.93294
20 × 20 ft6 in8.1510.39440
24 × 24 ft4 in7.829.97423
24 × 24 ft6 in11.7314.96634

Field guide for pea gravel

Measure the material footprint

Use the inside edge of the border when measuring a walkway. Break curves into short strips and average the widths within each strip. Include only areas receiving stone. Subtract permanent pads and steps, and measure the open bed depth from the prepared base to the intended gravel surface. For an existing path, measure the additional depth needed in several places before ordering a full replacement layer.

Compare a sample against the intended use and review the supplier’s gradation. Keep a decorative finish quantity separate from any compacted base below it. The two products can have different densities and different delivery terms. For stone placed against edging, check the finish elevation at doors and transitions. A drawing showing the border, the delivery location and a route for moving the material helps a crew plan how to distribute a load.

Work through this estimate

Start with the geometry for 16 × 20 ft at 4 in. The footprint is 16 ft × 20 ft, which gives 320 square feet. Convert the depth to the same unit before multiplying. Dividing 4 inches by twelve gives 0.3333 feet. The footprint times that depth gives 106.67 cubic feet in place. Keep the full precision on the worksheet and round only the displayed result. For a tapered section, measure enough cross sections to represent the change in area.

The current worksheet adds 10% for handling and variation. Multiplying the measured volume by 1.1 produces 117.33 cubic feet to order. Divide that value by twenty-seven to convert to 4.35 cubic yards. A yard is three feet in each direction, which accounts for all twenty-seven cubic feet. If your supplier quotes a different order increment, round the final combined project quantity up to the next increment it actually sells.

For weight, the model uses 2550 pounds per cubic yard. Applying that density to the order gives 11081 pounds. Dividing by two thousand gives 5.54 US short tons. Treat weight as a planning estimate. Moisture, source material and packing affect actual loads. Obtain the supplier’s density before using a takeoff to plan hauling, and use the carrier’s verified payload limits when arranging delivery.

Compare the purchase units

One 0.5 cu ft bag covers 0.5 cubic feet under this model. Dividing the unrounded order volume by the bag yield and rounding upward gives 235 bags. Look at the measured yield on the product label when changing brands. A bag’s weight and the volume it contributes to the finished job describe different quantities. If the store stocks multiple sizes, each row is a complete alternative for the same job. Choose one size or prepare a separate mixed-size order.

The bulk allowance uses $38.00 per short ton and a delivery fee of $125.00. For this worksheet that gives $335.55 delivered, compared with $1,287.80 for the least expensive bag option. Get an itemized local quote covering minimum loads, delivery distance, tax and placement. Include any equipment or extra trips in your own comparison. A small change in the delivery charge can reverse the result on a modest job.

Mark the inside edge of the bed and split curved edges into measurable sections.

Subtract planted islands and paving before estimating the stone-covered area.

Check the package volume on the retailer’s label when comparing bags with loose stone.

Describe the intended surface to the supplier. Rounded decorative stone and crushed angular stone behave differently under traffic.

Frequently asked questions

How much material should I order for 16 × 20 ft at 4 in?

Allow 4.35 cubic yards (117.33 cubic feet), or 235 bags at 0.5 cu ft each. The estimate includes 10% waste.

How much pea gravel covers a 10 × 10 foot bed at two inches?

With 10% waste the estimate is 18.33 cubic feet, about 0.68 cubic yard. At 0.5 cubic foot per bag, order 37 bags.

Can I use a depth smaller than an inch?

Yes. Use the eighth-inch fraction selector to enter fractional depths. Keep the same depth basis across the sections you add together.

What density is used for pea gravel?

The planning value is 2,550 pounds per cubic yard. Local stone and moisture conditions can change the delivered weight.

How do I measure a tapered strip?

Split it into a rectangle and a triangle, or into shorter sections of reasonably constant width. Add their volumes before rounding to bags.