Retaining Wall Calculator
Wall face area is length times height. Divide by block face, apply waste from 0 to 40 percent, and round up. Optional depth sketches volume. Estimate only, not a permit, code check, or engineered design.
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How to estimate retaining wall blocks
- Enter wall length and exposed height in one unit.
- Enter block length and block height in that same unit.
- Set waste from 0 to 40 percent for cuts and breaks.
- Optionally enter block depth for a volume sketch, then read face area and blocks to buy.
Retaining wall block count
Face area takeoff with optional depth
| Face area | length × height |
|---|---|
| Block face | blockLength × blockHeight |
| Buy | ceil(raw × (1 + waste/100)) |
| Optional volume | face area × depth when depth > 0 |
| Omitted | Geogrid, drainage, batter, and surcharge |
| Compliance | Estimate only. Not engineered design. |
What this retaining wall count covers
Only the visible face rectangle is counted. Setbacks, curves, and caps need extras. CMU face math also appears on concrete block. Brick courses sit on brick.
How blocks to buy are computed
area = length × height. face = blockLength × blockHeight. raw = area / face. buy = ceil(raw × (1 + waste/100)). If depth is greater than 0, volume sketch = area × depth. Units must match across wall and block sizes.
Drainage, geogrid, and height limits
Tall walls often need geogrid, drain stone, and an engineer. This page never sizes those systems. Grade slope helpers are on grade. Backfill volume can start from excavation.
Use cases
A 40 by 4 ft garden wall with 16 by 8 in block faces typed in feet. Comparing 5% versus 10% waste. Not a stamped wall design.
Limits
No soil pressure, no grid length, and no frost depth. Estimate only, not a permit, code check, or engineered design. Nothing is uploaded.