Cost to Build a Retaining Wall (2026)
A retaining wall typically runs $20–$60 per square foot of wall face installed, depending on material (segmental concrete block at the low end, poured concrete or natural stone higher), wall height, drainage needs, and labor in your area. A common 20 ft long × 3 ft tall (60 sq ft) wall therefore lands around $1,200–$3,600 installed.
Where the money goes: labor is usually 50%+ of the total. Materials — blocks, cap blocks, a compacted gravel leveling pad, and clean drainage gravel behind the wall — make up the rest. Proper drainage (gravel backfill plus a perforated drain pipe) is what keeps a wall standing, so don’t skip it to save money.
Use the retaining wall calculator to size up exactly how many blocks and caps you need, plus the gravel base and drainage backfill, then get 2–3 quotes.
Ways to save: choose standard concrete block over natural stone, keep the wall low and straight (fewer cuts and no corners), and handle excavation and base prep yourself even if you hire out the block laying.
Permits: walls over 3–4 ft tall usually require an engineered design and a building permit — check your local codes before you start. Taller or tiered walls cost significantly more.
Frequently asked questions
How much does a retaining wall cost?
Block retaining walls run about $20–$60 per square foot of wall face installed; a 20x3 ft wall lands around $1,200–$3,600.
Do I need a permit for a retaining wall?
Walls over 3–4 feet tall usually require an engineered design and a building permit — always check your local codes first.
How many blocks do I need for a retaining wall?
Multiply blocks per course (wall length divided by block width) by the number of courses (wall height divided by block height). The calculator handles it.