How Much Stone to Fill a Gabion Basket: Tons and Sizes

Working out how much stone to fill a gabion basket comes down to one measurement and one conversion. Measure the inside of the basket in feet, turn that into cubic yards, then multiply by the weight of placed gabion rock, which is roughly 1.4 to 1.5 tons per cubic yard with the gaps between stones already counted. The other half of the job is picking stone that is big enough to stay in the cage and hard enough to last. This guide walks through the math for common basket sizes and a full wall, explains why you should not subtract the voids a second time, and covers stone size, stone type and how to fill a basket so it does not sag.

Open the crushed stone calculator →

The short answer

Volume: length × width × height in feet, divided by 27, gives cubic yards. A 3 × 3 × 3 ft basket holds exactly 1 cubic yard.
Weight: plan on about 1.4 to 1.5 tons of stone per cubic yard of basket. That figure already allows for the empty space between rocks.
Extra: add about 5% to 10% for settling, broken pieces and hand sorting.
Size: the smallest stone must be larger than the mesh opening. With the common 3-inch mesh, 4 to 8 inch stone is the usual fill.

Step 1: measure the basket volume

Use the inside dimensions of the cage, or the finished size of the wall you are building if you will cut the last basket short. Then:

Cubic yards = length (ft) × width (ft) × height (ft) ÷ 27

If your baskets are sold in metric sizes, multiply cubic meters by 1.31 to get cubic yards. Count every basket, including the ones that will be buried as a footing course.

Step 2: convert cubic yards to tons

Tons = cubic yards × 1.4 to 1.5, then add 5% to 10%.

Use the low end for rounded cobbles or single-size stone dumped in loosely. Use the high end for angular crushed rock with a range of sizes that is placed by hand, because the smaller pieces fill some of the gaps between the larger ones. In metric terms the same range works out to roughly 1.65 to 1.8 tonnes per cubic meter.

Why you do not subtract the voids again

A filled gabion is only about 60% to 70% solid rock. The rest, roughly 30% to 40%, is air between stones. It is tempting to take the basket volume, knock off a third for the gaps, and then multiply by a rock weight. The trouble is that the 1.4 to 1.5 ton figure is already the weight of rock as it sits in a basket, gaps and all. Taking the voids off twice leaves you about a third short.

You can check the number from the other direction. Solid granite or hard limestone weighs about 165 pounds per cubic foot, which is about 2.2 tons for a full cubic yard with no gaps. Take away 35% for voids and you land near 1.45 tons, right in the middle of the range.

Stone needed for common basket sizes

Basket size (L × W × H)	Cubic yards	Stone (tons)	Order with ~10% extra
3 × 3 × 3 ft	1.0	1.4 to 1.5	about 1.6
6 × 3 × 1.5 ft	1.0	1.4 to 1.5	about 1.6
6 × 3 × 3 ft	2.0	2.8 to 3.0	about 3.2
9 × 3 × 3 ft	3.0	4.2 to 4.5	about 4.8
12 × 3 × 3 ft	4.0	5.6 to 6.0	about 6.4
4 × 1.5 × 1.5 ft (planter or bench)	0.33	0.47 to 0.5	about 0.55

For a small garden piece, bagged decorative stone can make sense. The 4 × 1.5 × 1.5 ft box above needs roughly 950 to 1,000 pounds of rock, or about 20 bags at 50 pounds each, before any extra.

Worked example: a gabion retaining wall

Say you are building a wall 24 feet long with two courses of 3 × 3 × 3 ft baskets, one on top of the other.

Bottom course: 24 × 3 × 3 = 216 cubic feet, or 8 cubic yards
Top course: another 8 cubic yards
Total: 16 cubic yards
Stone: 16 × 1.4 = 22.4 tons to 16 × 1.5 = 24 tons
With 5% to 10% extra: about 23.5 to 26.4 tons, so ordering around 25 tons is reasonable

If the wall steps back as it rises or uses a wider footing course, figure each course on its own and add them up. A wall this size also needs a level base. Our guide to retaining wall base gravel covers that layer, and crushed stone for retaining wall backfill covers what goes behind it.

What size stone to use

Bigger than the mesh. If the smallest rocks can slip through the openings, they will work their way out over time and the basket will slump. Measure the actual opening rather than going by the product name.
4 to 8 inch for 3-inch mesh. This is the most common pairing for welded and woven baskets. Larger stone works but leaves bigger gaps and can bulge the faces.
Thin baskets and mattresses. Shallow units, such as 6 to 12 inch mattresses used to line channels, often call for smaller stone. Follow the maker's size range.
Ask for a graded load. A mix within the size range packs tighter than stone that is all one size.

Which type of stone works best

Angular crushed stone such as granite, basalt, trap rock or hard limestone locks together, packs densely and settles less. It is the usual choice for walls that hold back soil.
Rounded river rock or cobbles look good and are popular for decorative pieces. They leave more space between stones, so they weigh a little less per yard and can shift as they settle.
Avoid soft or flaky stone. Shale, sandstone that crumbles, and other rock that breaks down when it freezes and thaws can turn to rubble inside the cage.
Face and core. On garden walls, some builders set the nicest stone by hand along the visible faces and fill the hidden middle with cheaper rock. If the wall was designed by an engineer, use only the stone the plans call for.

If you are pricing a few options, our guides to how much a yard of crushed stone weighs and how much a yard of river rock weighs help you compare loads sold by the ton with loads sold by the yard.

How to fill a gabion basket

Set the empty basket in place on a level, compacted base. Filled baskets weigh well over a ton each, so they are assembled and filled where they will stay.
Fill in layers about a foot deep. Place the flatter, better-looking stones against the outside faces by hand and fill the middle behind them.
Add the bracing wires that come with the kit. On 3-foot baskets they usually go across each cell at about one-third and two-thirds of the height to keep the faces from bowing out.
Fill neighboring cells together so one cell is never more than about a foot higher than the next one. That keeps the dividers straight.
Overfill slightly, by an inch or two, before closing the lid. The stone settles, and a lid pulled tight over a full basket stays tight.

For walls that retain soil, a filter fabric behind the baskets keeps fines from washing through the stone. Many towns require a permit or an engineer's design for retaining walls above about 4 feet, so check before you order the rock.

Ordering tips

Ask for gabion stone by name and give the size range and the mesh opening. Yards often stock a specific product for it.
Get the yard's weight per yard. If they quote a different figure, use theirs. Moisture and rock type change it.
Plan the drop spot. Most baskets are filled by hand or with a small loader, so have the load dumped as close to the wall as the truck can safely reach.
Order a little extra. A short load means a second delivery; leftover stone always finds a use as a drain bed or path edging.

Questions people ask

How much stone does a 3x3x3 gabion basket hold?

A 3 x 3 x 3 ft basket is exactly 1 cubic yard, so it takes about 1.4 to 1.5 tons of gabion stone. With a little extra for settling, order about 1.6 tons per basket.

What size stone goes in a gabion basket?

The smallest stones must be larger than the mesh opening so they cannot slip out. For the common 3-inch mesh, 4 to 8 inch stone is the usual fill. Shallow mattresses often use a smaller range set by the maker.

Should I subtract the gaps between stones when I order?

No. The 1.4 to 1.5 tons per cubic yard figure already describes rock as it sits in a basket, voids included. Subtracting the gaps again leaves you about a third short.

Can I fill a gabion with river rock?

Yes, and rounded cobbles look good in decorative pieces. They leave more space between stones and can shift as they settle, so angular crushed stone is the better pick for walls that hold back soil.

How heavy is a filled gabion basket?

Roughly 1.4 to 1.5 tons per cubic yard of basket, so a 6 x 3 x 3 ft unit weighs around 2.8 to 3 tons once full. Set baskets in place empty and fill them where they will stay.

Can I use cheaper stone in the middle of the basket?

On many garden walls, builders hand-place nicer stone along the visible faces and fill the core with cheaper rock. If an engineer designed the wall, use only the stone the plans specify.

As an Amazon Associate, AsphaltTons.com earns from qualifying purchases. Product links below are sponsored.