Gravel Calculator — Oregon

The estimate starts with the area you are covering and the depth of stone you want on top of it. The calculator multiplies area by depth for a volume in cubic feet, divides by 27 to reach cubic yards, and then multiplies by the material's density to give a weight in tons, because most bulk gravel is sold by the ton.

You can enter the area two ways. Give a length and width for a plain rectangle, or type a square-foot area directly when the shape is irregular and you have already worked it out. Depth goes in as inches and the formula converts it to feet, so a 2-inch decorative layer becomes one-sixth of a foot.

The density step turns volume into an order. Landscape gravel and crushed stone average about 1.4 tons per cubic yard, so the tool multiplies your cubic yards by 1.4 for tons. That figure shifts a little by stone type, since a dense crushed rock runs heavier and a light, airy stone runs lighter, so treat the tonnage as an estimate to confirm with your yard.

The tool reports both cubic yards and tons and adds a small allowance you set for spreading losses and uneven ground. Decorative gravel is not a material you compact, so that allowance covers waste and even coverage, not the shrink that a packed base needs.

Gravel is bought for two very different jobs, and the stone that is right for one is wrong for the other. Decorative and landscaping gravel is chosen for how it looks and how it covers the ground: color, size, and texture across a bed, a path, or a border. Structural stone, such as road base or a paver sub-base, is chosen to carry weight and lock into a hard layer. This calculator sizes the quantity for either, but the stone you order should match the job.

Decorative gravel sits on the surface and is judged by eye. You pick it for a clean look over a bed, a soft crunch underfoot on a path, or a low-maintenance ground cover that needs no mowing. It does not have to bear a car or hold a grade under load, so appearance and feel drive the choice rather than strength.

Structural stone is the opposite. Road base is a dense blend of angular crushed rock and stone fines that packs into a firm, load-bearing platform under a driveway, a slab, or pavers. If your project has to carry vehicles or support a hard surface, that is a base-stone job, and the road base calculator is the right tool for it. Do not use a loose decorative stone where a packed base belongs.

Knowing which job you have keeps both the stone choice and the depth honest. The rest of this guide covers gravel in its decorative and landscaping role: choosing a size and shape, spreading it to the right depth, and keeping it in place once it is down.

Gravel is sorted by size, and the size you pick sets both the look and how the stone behaves underfoot. Yards label the clean, screened sizes by number. A number 57 stone is a popular all-purpose landscape and drainage gravel at about three-quarters of an inch, large enough to read as stone and open enough to drain. A number 8 stone is smaller, about three-eighths of an inch, and suits narrow paths and the joints between pavers. The smaller the stone, the smoother the surface and the easier it is to walk on.

Shape matters as much as size. Crushed stone has sharp, broken faces. River and pea gravel are rounded and smooth from water tumbling. Pea gravel is a small rounded stone, about three-eighths of an inch, prized for a soft look and a comfortable feel on patios and paths. A crushed granite or limestone gives a more angular, structured look and a firmer walking surface.

Clean versus with-fines is the last split. A washed or clean stone, like a number 57, has the dust rinsed out, so it stays loose and drains freely. A crushed stone sold with its fines still in it packs tighter, which reads more like a base material than a decorative cover. For a surface you want to look like distinct stones, order a clean, washed size rather than a blend full of dust.

Match the size to where it goes. A larger stone makes a bold cover for a bed or a border and resists washing away in a downpour. A smaller stone gives a neat, even path that is kind to bare feet and easy to rake level. Order the size for the look and the use, then size the quantity the same way whichever stone you choose, since the density barely moves between landscape gravels.

The single most useful thing to understand about decorative gravel is how its shape decides whether it stays put. Angular crushed stone has jagged, broken faces that catch on each other, so a crushed-stone path or bed knits together loosely and holds a crisp edge and a mild slope reasonably well. Rounded river and pea gravel have smooth faces that roll past one another, so they scatter, migrate underfoot, and creep downhill over time.

This is the clean line between decorative gravel and road base. Road base locks into a hard, load-bearing layer precisely because its angular stone and fines compact and interlock. Rounded river gravel and pea gravel do the opposite. They do not compact and they do not interlock, so they can never form a stable base. A rounded stone is a surface cover, never a structural layer, no matter how deep you pour it.

The practical result is that rounded gravel needs to be contained. On a patio or a path, loose pea gravel wants to spread into the lawn and thin out in the middle, so a firm edge is not optional. Walking shifts it, rain moves it, and a slope drains it to the low end. Plan for edging and a flat or gently graded layout wherever you use a rounded stone.

Angular crushed stone is more forgiving. It still benefits from an edge, but it holds a path or a border with less drift and tolerates a mild slope better. If you want a gravel surface that stays where you rake it, lean toward an angular crushed stone. If you want the soft look and feel of a rounded stone, accept that you are signing up for edging and the occasional top-up.

Depth is the biggest lever on how much gravel you order, and for a decorative layer the right depth depends on what you want the stone to do. A thin layer is enough to change the color of a surface, while a thicker layer is what actually hides the ground and holds back weeds. Set the depth before you calculate, because it drives the tonnage directly.

A top-dressing of 1 to 2 inches is enough to refresh the color of an existing gravel surface or to give even coverage over a bed that already has a base under it. It is the lightest, cheapest option, but it will not hide bare soil on its own and weeds push through it easily.

A decorative layer of 2 to 3 inches is the common choice for a new gravel bed, border, or light path. It gives full, even coverage so the ground does not show through, and it reads clearly as a gravel surface rather than a dusting. Most landscaping gravel is spread in this range.

For real weed suppression and a surface that stays covered, aim for 3 to 4 inches over a landscape fabric. The extra depth blocks the light weeds need and keeps soil from working up through the stone. Going much deeper than that wastes material and can feel loose and unstable underfoot, especially with a rounded stone, so 3 to 4 inches is usually the practical ceiling for a decorative cover.

A decorative gravel surface lasts when the ground under it and the edges around it are handled, and the calculator's job ends at the quantity, so plan these alongside the order. Two features do most of the work: a fabric under the stone and a firm edge around it.

Landscape fabric goes between the soil and the gravel. It slows weeds from growing up through the stone, and it keeps the gravel from sinking into and mixing with the soil, which is what turns a clean stone bed muddy over a season or two. A woven geotextile under a path or a bed is cheap insurance that keeps the gravel reading as gravel. It does not stop seeds that blow in and root in debris on top, so an occasional weeding is still part of the deal.

Edging is what keeps loose stone where you put it. Steel, aluminum, stone, brick, or timber borders hold the gravel against a lawn, a bed, or a path so it does not migrate outward and thin in the middle. This matters most for rounded pea and river gravel, which roll and spread far more than an angular crushed stone. Without an edge, you top up a loose gravel area far sooner and fight stone in the grass.

Prepare the ground first. Strip sod and weeds, grade the surface roughly level or to a gentle drainage slope, lay the fabric, set the edging, then spread the gravel in an even layer and rake it flat. A decorative surface does not get compacted the way a base does, so the work is in the fabric, the edge, and an even spread rather than in rolling the stone.

A few predictable errors account for most short or over-orders on a decorative gravel job, and they differ from the mistakes that trip up a structural base. Knowing them up front saves a second delivery or a leftover pile.

The most common is spreading too thin for the goal. A 1-inch scatter will not hide soil or hold back weeds, so people who size for a token layer end up ordering more within the season. Decide first whether you want color only or full weed-suppressing coverage, then set 1 to 2 inches or 3 to 4 inches to match, and size the order to that depth.

Choosing the wrong shape is next. Using a rounded pea or river gravel on a slope or in an unedged area means the stone migrates and scatters, and no amount of extra tonnage fixes a stone that will not stay put. Where drift is a concern, pick an angular crushed stone or commit to firm edging before you order.

Unit confusion bites here as it does with any bulk stone. Depth is in inches while length and width are in feet, and mixing them throws the volume off badly. Gravel is also sold by both the ton and the cubic yard, so order the right number in the unit your supplier quoted. Finally, size odd shapes honestly: break a curved bed or an irregular border into simple rectangles, size each in the calculator, add them, and round up so a small margin covers spreading and uneven ground.