Retaining Wall Cost Calculator
A 40-foot retaining wall three feet high runs about $5,560 in Atlanta in segmental block — $3,955 to $7,164. That is $139 a linear foot, and the linear foot is the misleading unit: the same wall at six feet is $319. Walls are paid for by square foot of built face, and the built face includes the buried course nobody counts — 152 square feet here rather than the 120 you can see.
Estimate the cost for your home
Estimated cost of the retaining wall
$5,758
typical · range $4,146 to $7,370 · 40 ft long × 3 ft visible = 152 sq ft of built face · $144 per linear ft · $37.88 per sq ft of face
Labour priced at national wages. Enter a ZIP code to price it for your area. 66% of this figure comes from modelled material prices — each line shows its own uncertainty.
Priced from bls.gov Aug 2026how every line is sourced
The one input that changes the answer for you.
The default in American gardens and usually the right answer. Dry-stacked interlocking blocks with a batter built into them, no mortar and no footing to pour. ⚠️ Its whole engineering is the geogrid buried behind it: above about three feet the wall does not stand by weight, it stands because layers of mesh tie it into the soil it is holding. A quote that does not mention geogrid on a tall segmental wall is a quote for a wall that will lean.
What most gardens have and what this page prices as its baseline. Enough fines to hold some water, enough structure to compact properly.
What the soil is worth
| Sandy or gravelly — water drains away | 6.6 t | $5,590 |
|---|---|---|
| Loam or mixed — the ordinary case | 8.3 t | $5,758 |
| Clay — water sits and the soil swells | 11.2 t | $6,039 |
Only $449 between the easiest soil and the hardest on this wall, which is a smaller gap than people expect — the drainage stone scales but it is not the biggest line. ⚠️ The soil matters far more for whether the wall survives than for what it costs. Clay holds water, and water behind a wall is weight: a saturated backfill can roughly double what the wall is being asked to resist. That is a drainage question, and drainage is the line a cheap quote removes because none of it is visible afterwards.
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The figure above is already calculated. Each step just makes it more yours, and you can stop at any of them.
Why a price per linear foot tells you nothing
| Visible height | Stone | Per linear ft | Per sq ft of face | Cost |
|---|---|---|---|---|
| 2 ft | 6.2 t | $105 | $38.91 | $4,203 |
| 3 ft | 8.3 t | $144 | $37.88 | $5,758 |
| 4 ft | 10.4 t | $189 | $38.62 | $7,570 |
| 5 ft · engineered | 12.4 t | $284 | $47.28 | $11,346 |
| 6 ft · engineered | 14.5 t | $328 | $46.24 | $13,131 |
Compare the two rate columns. Per linear foot the price runs from $105 to $328, while per square foot of face it hardly moves — $38.91 against $38.62 across the first three rows. So the cost tracks face area almost exactly, and a price per linear foot only means something if the height is quoted beside it — which it never is. That is why two per-foot quotes cannot be compared, and why the useful question to ask a contractor is what they charge per square foot of built face. ⚠️ The one genuine step is the threshold: above about 4 feet of retained height most jurisdictions want a permit and a stamped design, and that is the only place in the table where the rate per square foot jumps — $3,776 for one extra foot.
Five materials, and how long each one lasts
| Material | Service life | Per year | Cost |
|---|---|---|---|
| Segmental concrete block | 50 yrs | $115 | $5,758 |
| Poured reinforced concrete | 75 yrs | $133 | $10,004 |
| Pressure-treated timber | 20 yrs | $237 | $4,742 |
| Natural stone | 100 yrs | $137 | $13,682 |
| Gabion baskets filled with rock | 40 yrs | $170 | $6,809 |
⚠️ Read the middle column before the last one. Pressure-treated timber is the cheapest wall here to build and the most expensive to own — timber against wet soil has a couple of decades in it whatever the treatment, and replacing it means digging out everything planted behind it. Natural stone is the dearest to build and among the cheapest per year, because a properly built stone wall outlives the people who commissioned it. The service lives are declared estimates, not measurements, and they assume the drainage was done properly — which is the thing that actually decides whether any of these numbers hold.
| Line item | Qty | Cost | Source |
|---|---|---|---|
| Segmental concrete block — wall materialsquare feet of built face, when this material is chosen | 152sq ft of face | $1,672–$3,952 | estimated±41% |
| Excavation behind and below the wallcubic yards, doubled without machine access | 5.6cu yd | $123–$325 | estimated±45% |
| Compacted base and free-draining backfilltons of base plus drainage stone, scaled by soil | 8.3ton | $282–$647 | estimated±39% |
| Perforated drain pipe, geotextile and outletswall length plus 15% for the run to daylight | 46linear ft | $156–$391 | estimated±43% |
| Setting the wallsquare feet of face × hours per sq ft for the material | 24.3hour | $1,409–$1,514 | sourced |
| Placing base, drainage stone and backfilltons × 0.9 hours, ×1.8 without machine access | 7.5hour | $330–$355 | sourced |
| Machine operationcubic yards × 0.55 hours, with machine access | 3.1hour | $173–$186 | sourced |
| Total | $4,146–$7,370 | ±28% |
Where these numbers come from
- The unit is face area, and nobody quotes it
- Height grows several things at once, and only one of them is the wall. The face area grows. The excavation behind it grows. The drainage stone grows — 6.2 tons at two feet against 14.5 at six. On a segmental wall the geogrid appears above about three feet and repeats every few courses. Because all of them scale together, the price per square foot of built face stays close to flat — $37.59 at two feet and $37.32 at four — while the price per linear foot goes from $102 to $183. One of those two numbers is comparable between quotes and the other is not, which is the whole practical point: ask what a contractor charges per square foot of built face, and give them the height. ⚠️ The one real break in the pattern is the engineering threshold. If a design sits just above 4 feet, it is worth asking whether it could sit just below — one foot is worth $3,721 here, and it is the only step in the table.
- You pay for a wall you never see
- About a tenth of the visible height goes below grade, and the compacted base sits under that. A wall showing 3 feet is 3.8 feet of built wall, so there are 32 square feet of face on this run that get paid for and never looked at. That is not padding and it is not optional: the buried course is what stops the bottom of the wall kicking out, and it is why a wall built straight onto the ground moves in its first winter. It also explains a common confusion in quotes — a price per square foot and a price per foot of visible height are not the same number and they never were.
- What holds the wall up is not the wall
- A retaining wall does not fail because the block was poor. It fails because water got into the soil behind it and the soil got heavier. USGS Water Science School, Infiltration and the water cycle covers how rain gets into the ground behind a wall in the first place, and EPA, Soak Up the Rain covers where the rain on your plot goes, both retrieved 2026-08-24. Before anybody quotes, look your address up on USDA NRCS, Web Soil Survey — it is free, it says what your soil is made of, and it is the single most useful thing you can know before a wall is designed. ⚠️ On a segmental wall above about three feet the thing actually holding the bank back is the geogrid buried behind the blocks, not the blocks. A quote for a tall segmental wall that never mentions grid is worth questioning before it is worth comparing. Deep excavation on a bank is also where 29 CFR 1926 Subpart P, Excavations (govinfo.gov) starts to apply.
- Cheap to build, expensive to own
- The material comparison changes completely when service life is put beside the price. Pressure-treated timber is the cheapest wall here at $4,559 and the dearest per year at $228, because timber against wet soil has about 20 years in it whatever the label says — and replacing it means digging out everything planted behind it in the meantime. Natural stone is $13,272 to build and $133 a year. ⚠️ Those service lives are declared estimates rather than measurements, and every one of them assumes the drainage was done properly. Access matters too and it is easy to check before asking for prices: without a route a machine can use, this wall goes from $5,560 to $6,786, because 8.3 tons of stone then move by barrow. Wages from BLS OEWS, May 2025, retrieved 2026-08-20, with benefit load from BLS ECEC. Material bands cover 5 wall types.
- Material prices
- Modelled estimates, not sourced prices. No public, machine-readable source of US residential material prices exists, and we would rather say so than pretend otherwise. Each line carries its own uncertainty band. How we estimate them.
Contractor overhead and profit applied at 33–43% over direct cost. Data last reviewed 2026-08-24.
What this figure does not include
- Fixing why the ground is moving
- A wall built to hold a bank that is actively sliding is a wall in the way of a landslide. Where there is real slope instability the question is geotechnical and it comes before any price for block.
- Removing the old wall
- Taking out a failed timber or block wall, and dealing with whatever comes down with it, is its own job — and it is unpredictable, because nobody knows what is behind it until it is out.
- Landscaping above and below
- Levelling, topsoil, planting and turf are what makes the finished thing look like anything. None of it is priced here.
- Utilities in the way
- Digging a trench along a boundary finds gas, water, irrigation and cable often enough to be worth planning for. Call 811 before anybody breaks ground; locating is free and hitting a line is not.
- Tiered walls
- Two shorter walls stepped back look like a way round a height limit and are not: each wall surcharges the one below unless the setback is large enough, and the pair is normally engineered as a single taller structure.
- What the neighbours think
- Retaining walls sit on boundaries, change where water goes, and outlive the people who build them. A conversation and, where the boundary is unclear, a survey are worth more than any line on this page.
Questions people actually ask
How much does it cost to build a retaining wall?
About $5,560 in Atlanta for a 40-foot segmental block wall three feet high — $3,955 to $7,164, or $139 a linear foot. ⚠️ That linear-foot figure is the one the industry quotes and the one that misleads, because it only holds at that height. The same wall at six feet is $319 a linear foot. What stays roughly steady is the rate per square foot of built face — $36.58 against $44.95 — which tells you the trade prices face area and the marketing prices length.
How do you calculate the cost of a retaining wall?
By square foot of built face, and the built face is taller than the wall you see. About a tenth of the height goes below grade and there is a compacted base under that, so a wall showing 3 feet is 3.8 feet of wall — 152 square feet of face on a 40-foot run rather than the 120 you would count from the garden. Multiply that face area by a rate for the material, then add the four things that scale with height and not with length: excavation, drainage stone, the pipe, and on a segmental wall the geogrid buried behind it. This calculator does all of that and shows both rates side by side.
How much is a 4 ft retaining wall?
About $7,315 for 40 feet of segmental block in Atlanta — $183 a linear foot. ⚠️ Four feet is also where the interesting thing happens: most jurisdictions want a permit and an engineer-stamped design above roughly 4 feet of retained height, so five feet is $11,035 rather than a proportional step up. That is a 51% jump for one extra foot. The threshold is local rather than federal, it drops where something is parked or driven above the wall, and your building department is the authority — but if a design is hovering just above four feet, it is worth asking whether it could sit just below.
What is the cheapest retaining wall to build?
Pressure-treated timber, at $4,559 against $5,560 for segmental block on the same wall — and it is the most expensive one to own. ⚠️ Timber against wet soil has about 20 years in it whatever the treatment, so it works out at $228 a year against $111 for block and $133 for natural stone, which is the dearest to build and among the cheapest to keep. Replacing a timber wall also means digging out everything planted behind it. The genuinely cheapest option is often not a wall at all: a gentler regraded slope holds itself up for nothing.
Why do retaining walls cost so much?
Because most of what you are paying for is buried. On this wall the block itself is a minority of the price; the rest is 5.6 cubic yards excavated, 8.3 tons of drainage stone placed and compacted in layers, a perforated pipe taken to daylight, and — above three feet on a segmental wall — layers of geogrid tying the wall into the soil behind it. ⚠️ None of that is visible when the job is finished, which is exactly why it is the first thing a cheap quote removes. A wall holds back soil; what pushes a wall over is water in that soil, and everything on this page that you cannot see afterwards exists to stop the water becoming weight.
How much does it cost to build a 100 foot retaining wall?
About $13,899 at three feet high in Atlanta — $139 a linear foot, against $139 for the 40-foot wall. It scales close to linearly with length, which is the one dimension that does behave the way people expect: the same cross-section repeated further. Height is what breaks the arithmetic, not length. The other thing that moves at this size is access — 20.7 tons of stone have to reach the wall, and if a machine cannot get there the same wall is 22% more even at 40 feet.
Taken from Google’s “people also ask” results for this search on 2026-08-24, not invented.
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- How we calculate
The formula, the sources, and an honest account of which parts of the model are weak.