Gabion Wall Calculator
How many wire baskets your gabion wall needs by course and depth, the tons of fill stone to order with basket voids already accounted for, plus lacing wire, filter fabric and base gravel — and a gravity base-thickness check that tells you whether the wall is thick enough to stand.
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Gabion walls are bought by the basket, but they fail by the ton
A gabion wall is a gravity structure: it holds the bank back because it is heavy, not because it is anchored. That makes the material list unusual. The baskets are the cheap, visible part of the order; the fill stone is where the money and the weight actually are, and the two things most people get wrong are ordering stone as if the baskets were solid, and building the wall too thin to stand up. This calculator sizes the whole order — baskets by course and depth, fill stone in tons with voids already handled, lacing wire, filter fabric and base gravel — and checks the wall's thickness against the ratio gravity walls are designed to.
How each number is worked out
- Courses and built height: gabion walls go up in whole baskets, so the course count is (exposed height + minimum embedment) ÷ basket height, rounded up. The surplus does not become extra exposed wall — it becomes embedment. With 1.5 ft baskets a 3 ft wall is built 4.5 ft tall and buries 1.5 ft. Basket height, not preference, is what sets how deep the wall sits.
- Baskets: length ÷ basket length rounded up gives the baskets per course; base thickness ÷ basket width rounded up gives how many deep the bottom is. Upper courses step back by one basket at the interval you set, so a tall wall is a wedge rather than a column.
- Fill stone: the wall's actual volume × a placed density of about 1.4–1.5 tons per cubic yard. Note this follows the wall you are building, not the baskets you are buying — a 20 ft wall needs four 6 ft baskets per course but you cut the last one down, so you fill 20 ft of wall and not 24. That density already includes the 25–35% voids between stones, so the voids are not subtracted again — doing both is the classic way to under-order by a third. An overfill allowance covers settling and breakage.
- Base-thickness check: gravity gabion walls are normally built with a base 50–70% of the built height. The tool compares your basket depth against that band and warns when the wall is too thin, which is the failure nobody catches until it leans.
- Stone vs mesh check: the smallest dimension of the fill rock must exceed the mesh opening or the stone works its way out. 4–8 in graded rock in a 3 in mesh is the usual pairing; the tool flags the combination if yours conflicts.
- Fabric, wire and base: filter fabric covers the back face plus an overlap, lacing wire is counted per basket, and a compacted gravel base course runs under the footprint with an overhang each side.
Where these prices come from
Gabion baskets are usually quoted per project rather than listed at shelf prices, so the defaults here are anchored to real 2026 US retail listings where we could find them: a 9 × 3 × 3 ft galvanized woven basket at $164.85 and a 6 × 3 × 1.5 ft PVC-coated basket at $142.52. The galvanized 6 × 3 × 1.5 and 3 × 3 × 3 presets are scaled estimates from those two points, not quoted prices — treat them as placeholders and type in your supplier's number. Fill stone at $50/ton sits inside the $30–60/ton range gabion and rip-rap stone commonly sells for, with granite at the top of that band and freight often the largest single variable.
This tool estimates a gravity gabion wall built from stacked wire baskets. For segmental concrete block walls use the full block takeoff; for a wood wall see the timber calculator; to compare installed prices across materials see the cost calculator; and for the dig and haul-off under any wall see the excavation calculator. Defaults follow common gabion practice, not a specific engineered design — every field is editable.
Gabion tips that save a second delivery
- Order stone by placed weight, not by solid volume. The 1.4–1.5 tons per cubic yard figure is what suppliers mean by gabion rock; subtracting voids on top of it under-orders badly.
- Check the mesh before you buy the rock. The smallest rock dimension has to beat the mesh opening. A load of 3 in stone for a 3 in mesh is a load you cannot use.
- Angular beats round. Blocky quarried rock interlocks and faces cleanly; rounded cobble rolls, leaves voids and bulges the mesh.
- Hand-face the outside, dump the middle. Placing the visible face by hand and machine-filling the core is what separates a wall that looks built from one that looks tipped.
- Fabric between stone and soil, always. Without it, fines migrate into the rock and the wall slowly settles and stains.
Frequently asked questions
How many gabion baskets do I need?
Divide the wall length by the basket length and round up for baskets per course, then multiply by the number of courses (built height ÷ basket height) and by how many baskets deep the wall is. A 20 ft long, 3 ft exposed wall in 6 × 3 × 1.5 ft baskets is 3 courses of 4, one deep — 12 baskets. Enter your wall for its own count.
How much stone does a gabion wall need?
About 1.4–1.5 tons per cubic yard of wall volume, voids included. The 20 ft wall above is 270 cubic feet of basket — roughly 10.5 cubic yards once an overfill allowance is added, or about 14.7 tons of 4–8 in rock.
Are gabion walls cheaper than block walls?
Usually cheaper to build than engineered segmental block for the same height, especially as a DIY job, because the baskets are simple and there is no geogrid or adhesive. But gabion is stone-heavy, so the fill and its freight dominate the bill. Compare installed prices across materials in the cost calculator.
Do gabion walls need drainage behind them?
The wall itself is free-draining, which is one of its advantages — but you still want filter fabric between the rock and the retained soil so fines cannot wash into the baskets. On a wall retaining a wet bank, a collector pipe behind the base is still worth having; size it in the drainage calculator.
How long do gabion baskets last?
Coating decides it. Plain galvanized wire is the shortest-lived, heavier zinc or Galfan coatings last considerably longer, and PVC-coated wire is the choice near salt or moving water. The wire, not the rock, is what eventually fails.