Retaining Wall Calculator
Estimate retaining wall blocks, base gravel, backfill, and drainage allowance.
Construction Project Planner
Plan the wall, materials, packaging and budget
Enter your actual project dimensions, calculate an auditable material estimate, then adjust assumptions or save a comparison scenario. Nothing is calculated until you choose Calculate materials.
Your project estimate
Procurement-style material summary
| Material | Calculated need | Order quantity | Assumption |
|---|
Assumptions and warnings
Scenario comparison
Saved scenarios stay in this page only and are not sent to analytics.
| Scenario | Area | Blocks | Base | Backfill | Cost | Action |
|---|
Methodology and formulas
- Wall face area
- Sum of each segment length × exposed height.
- Block count
- Wall face area ÷ block face area, rounded up after the editable waste allowance.
- Cap count
- Total wall length ÷ cap-unit length, rounded up after waste. Omitted when no cap length is entered.
- Base material
- Total wall length × entered base width × entered compacted depth, plus waste.
- Drainage backfill
- Each segment length × exposed height × entered backfill width, plus waste.
- Packaging and cost
- Calculated quantities are rounded up to user-entered pallet, bag/package or roll sizes. Costs use only prices supplied by the user.
Rounding: indivisible blocks, caps, pallets, bags and rolls round up. Volumes display to two decimal places while calculations retain greater precision.
Last calculation-method update: 24 August 2026. Formula implementation is deterministic and covered by fixtures; no claim of professional engineering review is made.