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Retaining Wall Calculator

Estimate wall blocks, cap blocks, drainage gravel, and geogrid rows for a straight wall.

Reviewed
2026-09-05
Units
US + metric

Calculated result / live

26 wall blocks

Order 26 blocks plus 9 caps for 10.00 ft of wall.

16.0 in × 8.0 in block face, 12.0 in × 6.0 in base, 4.0 in drainage zone, 10% waste.

Input panel

Project measurements

Secondary quantities
Base wall blocks23
Ordered wall blocks26
Cap blocks9
Base gravel0.20 yd³
Drainage gravel0.27 yd³

Calculation trace

Formula with your numbers

10.00 ft × 2.00 ft ÷ (16.0 × 8.0 ÷ 144) = 23 blocks; + 10% = 26

26 wall blocks
01

What this retaining wall calculator calculates

A 16 ft × 2 ft wall with 16 × 8 in block faces needs 36 nominal blocks before waste and 12 cap blocks in a single row.

Formula

Wall face area ÷ block face area = blocks; length ÷ block length = caps; layer length × width × depth = gravel volume.

Worked example

With 10% waste, 36 blocks become 40. The 16 ft × 12 in × 6 in base is 8 ft³ before waste, separate from the drainage zone.

Ordering decision

Wall height, surcharge, soil, setback, geogrid, drainage outlet, and local limits govern whether a wall design is acceptable.

The page cites the applicable Uzi Tools reference table beside the calculator. Product labels, current editions, local code, and a licensed professional govern structural, electrical, and life-safety work.

02

How to use it

  1. Enter the measured dimensions and keep the displayed units beside each field.
  2. Review the retaining-wall blocks and drainage gravel result and the substituted formula before ordering.
  3. Adjust waste for the layout, cut pattern, product package, and site conditions.
  4. Copy or print the material list, then verify the cited product data and local requirements.
03

Retaining-wall blocks and drainage gravel

Use this retaining wall calculator for a straight wall with a specified block face, base, and drainage zone. It separates wall blocks, caps, base gravel, and back-drainage gravel.

04

Limits and professional review

Measurements, product yield, waste, moisture, and site conditions can change the order quantity. Local code and a licensed professional govern structural and electrical work.

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Data sources

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Related calculations

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Same-project tools

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Questions specific to this estimate