BUILDREFS Free Tools

Retaining Wall Block & Fill Calculator

Estimate block count, cap blocks, gravel backfill, deadman anchors, and filter fabric for segmental retaining walls.

Block Type

Block face: 12" wide × 8.0" tall | 5% waste included

Wall Length (ft)

Wall Height (ft)

Backfill Depth (ft)

How It Works

Blocks: Wall face area ÷ block face area + 5% waste.
Cap blocks: One row across the wall length.
Deadman: Every 3 courses for walls over 4 ft tall.
Gravel: Tapered drainage fill behind the wall.
Fabric: Filter fabric covers wall face + base.

Block Reference

Type	Size	Wt.
Standard	12"×8"	~30 lb
Large	18"×8"	~55 lb
Jumbo	24"×8"	~80 lb
Natural Stone	Varies	~50 lb

Field Tips

• Walls over 4 ft typically require a permit — check local codes.
• Bury the first course at least 1" per foot of wall height.
• Use clean crushed stone (¾" or #57) for drainage backfill.
• Install a drain pipe at the base to prevent hydrostatic pressure.

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