Cost guide · Retaining wall
How many blocks for a 30-foot retaining wall?
A 30 ft wall 2 ft high, built from 16 × 6 in blocks, takes 97 blocks: 4 courses of 23, plus 5% waste. Add 23 caps and 3.5 cu yd of crushed stone for the base and drainage. Materials come to about $889.50, with a likely range of $756.08 to $1,022.93.
Prices Ballpark U.S. home-center figures, not quotes. Default price list reviewed . Enter local prices in the calculator for a tighter number.
Materials takeoff
How many blocks for a 30-foot retaining wall? · https://estimahome.com/guides/retaining-wall-blocks-30-ft/
Wall length: 30 ftWall height, incl. buried course: 2 ft
- Courses
- 4
- Blocks per course
- 23
- Base gravel
- 1.28 cu yd
- Drainage stone
- 2.22 cu yd
| No. | Item | Qty | Unit | Unit cost | Amount |
|---|---|---|---|---|---|
| 1 | Wall block, 16 × 6 × 12 in | 97 | ea | $6.00 | $582.00 |
| 2 | Cap block | 23 | ea | $5.00 | $115.00 |
| 3 | Crushed stone, base and drainage | 3.5 | cu yd | $55.00 | $192.50 |
- Subtotal
- $889.50
- Likely range
- $756.08 – $1,022.93
- Bury the first course (often about 1 in per 8 in of wall height, at least one course). Include it in the height.
- Not included: drain pipe, filter fabric, construction adhesive for caps.
Buy these materials
Crushed stone is listed in the takeoff; order it in bulk from a landscape yard.
- 97 retaining wall blocksAmazon search for retaining wall blocks (opens in new tab)
- 23 wall cap blocksAmazon search for wall cap blocks (opens in new tab)
Links open a store search for each item. Check sizes and grades against your plan.
Open the retaining wall calculator with these inputsChange any measurement, assumption or price and the takeoff updates.
How the numbers work
- Blocks per course: 30 × 12 ÷ 16 in = 22.5, rounded up to 23.
- Courses: 2 × 12 ÷ 6 in = 4, including the buried course.
- Blocks: 23 × 4 × 1.05 = 96.6, rounded up to 97.
- Caps: 30 × 12 ÷ 16 in = 23.
- Base: 30 ft × 24 in trench × 6 in deep, plus 15% for compaction = 1.28 cu yd.
- Drainage stone: 12 in behind the full 2 ft height = 2.22 cu yd. Base plus drainage, rounded up to ½ yd: 3.5 cu yd.
- Cost: 97 × $6.00 + 23 × $5.00 + 3.5 × $55.00 = $889.50.
Comparison
| Height | Courses | Blocks | Stone | Materials |
|---|---|---|---|---|
| 1.5 ft | 3 | 73 | 3 yd | $718.00 |
| 2 ft | 4 | 97 | 3.5 yd | $889.50 |
| 2.5 ft | 5 | 121 | 4.5 yd | $1,088.50 |
| 3 ft | 6 | 145 | 5 yd | $1,260.00 |
Each row is a separate run of the Retaining Wall Calculator at default prices. The highlighted row is the project above.
What changes the cost
- Wall height
- Most block makers and many codes allow about 3 to 4 ft without an engineered design. Walls holding back a slope, a driveway or a structure, and tiered walls, need engineering and often a permit.
- Block style
- Blocks are 65% of this list at $6.00 each. Larger, tumbled or natural-face blocks cost more and change the count; enter the face length and height from the spec sheet.
- Drainage
- The stone behind the wall is not optional: water trapped behind a wall pushes it over. Most installs also run a perforated drain pipe at the base, wrapped in filter fabric. Neither the pipe nor the fabric is counted.
- Waste factor
- 5% covers chipped blocks and cuts at the ends. Curves and corners need more cuts and corner blocks.
- Labor versus DIY
- These are register prices for doing the work yourself. A contractor's bid adds labor, equipment, overhead, permit fees where they apply, and markup on materials, so it will run well above this figure. Get two or three written bids against the same plan and compare the material lists line by line. The base course takes the time: it has to be level in both directions, and every course above follows it.
- Regional prices
- Default prices are ballpark U.S. home-center figures. Expect them to differ by region, season, brand and grade. Enter your store's prices in the calculator and every quantity on this page reprices. Stone is cheapest by the yard or ton from a landscape supplier.
Questions
How many retaining wall blocks per square foot?
A 16 × 6 in block face is 0.67 sq ft, so 1.5 blocks per square foot of wall face before waste.
How much of a retaining wall goes underground?
At least one course, or about 1 in for every 8 in of wall height. Count the buried course in the height you enter.
How much gravel behind a retaining wall?
About 12 in of clean crushed stone behind the blocks for the full height. For this wall that is 2.22 cu yd.
Figures computed with the Retaining Wall Calculator and the default price list (/api/prices.json, reviewed October 20, 2026). Quantities are rounded up to what stores sell. Updated 2026-10-20.