Landscape wall material estimator

Retaining Wall Block Calculator

Estimate retaining wall blocks, cap blocks, backfill gravel, waste, and material cost from wall length, wall height, and block face size.

Units

Wall length (ft)Wall height (ft)Block face length (in)Block face height (in)Cap length (ft)Drain-rock depth (ft)Waste / cuts (%)Cost per block ($)Cost per cap ($)

Blocks to buy

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Cap blocks

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Backfill gravel

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Estimated cost

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Retaining walls need site-specific checks

This is a material count only. Drainage, geogrid, surcharge loads, soil, footing, wall height limits, permits, and manufacturer rules must be checked before building.

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Retaining wall block formula

Wall face area = length × height

Blocks = wall face area × (1 + waste %) ÷ block face area

Caps = wall length ÷ cap length

Backfill yd³ = length × height × drain-rock depth ÷ 27

Example

A 24 ft long by 3 ft high wall using 16×6 in blocks with 8% waste needs about 98 blocks, 24 one-foot caps, and about 1.78 yd³ of drain rock if backfilled 8 in thick.A 7.2 m by 0.9 m wall using 400×150 mm blocks with 8% waste needs about 117 blocks, 24 caps, and about 1.3 m³ of drain rock at 200 mm thick.

Retaining Wall Block Calculator FAQ

How does this retaining wall block calculator work?+

It multiplies measured job dimensions by the coverage, spacing, or package yield you enter, adds waste, then rounds the buy quantity up. The calculator counts visible face blocks and cap blocks, then estimates a drain-rock column behind the wall.It multiplies measured job dimensions by the coverage, spacing, or package yield you enter, adds waste, then rounds the buy quantity up. The calculator counts visible face blocks and cap blocks, then estimates a drain-rock column behind the wall.

Should I use the default waste value?+

Use the default for a quick planning estimate, then raise it for cuts, odd layouts, breakage, bad access, or product-specific loss.Use the default for a quick planning estimate, then raise it for cuts, odd layouts, breakage, bad access, or product-specific loss.

Is this a bid or code approval?+

No. It is a material planning calculator. Verify product data, local code, structural requirements, electrical requirements, and supplier packaging before ordering or building.No. It is a material planning calculator. Verify product data, local code, structural requirements, electrical requirements, and supplier packaging before ordering or building.