Count exact retaining-wall field units for a reviewed straight-wall course schedule, then reconcile explicit allowance, matching stock and supplier packs.
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Use this result well
A quick decision brief for this specific tool
Inputs that matter
Measured straight wall run, reviewed total whole courses including any buried course, one exact selected field-unit installed module, explicit field-unit allowance, usable matching stock, and exact current field units per supplier pack
Output to expect
Whole field units per course, base and allowance-adjusted demand, stock applied, new demand, whole supplier packs, available units and visible surplus
How it works
Round the straight-run module count to whole field units, multiply by the reviewed course schedule, apply only the entered allowance, subtract compatible stock, then round only new demand to exact supplier packs
Verify the exact selected system, installed module, total course/run schedule, connections, cuts, corners, curves, steps, tapers, caps, mixed units, lots and current packaging; nominal face dimensions are not an approved layout.
Obtain responsible design and jurisdiction review for soil, height, loads, groundwater, base, drainage, core/backfill aggregate, geogrid, global stability, excavation, permits and inspection; this field-unit count approves none of them.
Choose your path
Built around the job you need to finish
Count one exact standard field-unit product for a reviewed straight constant-run segmental retaining wall, then reconcile visible allowance, matching stock and current supplier packs without pretending to design the wall system.
Homeowner reconciling an approved small-wall layout
Turn a known straight run and course schedule into a transparent field-unit purchase count.
Copy the total course count, including any buried course, and the exact selected product's installed horizontal module.
Sees whole units per course, base demand and explicit allowance separately without fabricated caps, gravel or adhesive.
Landscape buyer using matching stock
Use verified leftover standard units before ordering current whole packs.
Confirm the exact product, size, finish, connection and lot requirements, then enter compatible stock and supplier pack quantity.
Stock is capped at reserve, new demand cannot go negative, and pack surplus stays visible.
Contractor reviewing a complex or engineered wall
Prevent a field-unit count from being mistaken for wall design or a complete material takeoff.
Keep changing runs, specialty units, caps, base, drainage, reinforcement, soil, load and jurisdiction requirements in their responsible reviewed schedules.
The record explicitly declines to approve geometry, stability, drainage, geogrid, permits or inspection.
Authoritative checks for this tool
Outputs and checklists are planning aids. Review the linked current authorities and the records, terms, instructions, and requirements that apply to your exact situation before a consequential decision.
Use one selected system's installed field-unit module. Nominal block-face dimensions do not establish a pattern, connection, setback, corner, curve or cut schedule.
Units per course = ceil(Straight run × 12 ÷ Exact installed horizontal module)
Reviewed course schedule and allowance
Copy the whole course count, including any buried course, from the responsible plan or exact system review. The allowance is visible and user-entered; zero adds none.
Reserve field units = ceil(Units per course × Reviewed total courses × (1 + Entered allowance%))
Stock and supplier packs
Apply only compatible whole stock, then round new demand to the current exact supplier pack. Available units and surplus remain visible.
Packs = ceil((Reserve field units − Usable matching stock) ÷ Exact field units per pack)
Updated: August 2026
Example Scenarios
Use the measured run, exact installed module and reviewed total course count for one standard field-unit SKU. The example keeps a buried course visible because it is entered, not inferred from height.
Verify product, size, finish, connection and lot requirements before counting leftover field units. The tool caps applied stock at the reserve and rounds only remaining demand to packs.
Do not pool corners, curves, steps, tapers, caps, multi-size patterns or changing course runs into this straight field-unit record. Build separate reviewed schedules for those products and segments.
Common Mistakes to Avoid
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Dividing wall face area by a nominal block face
✓
Use the exact installed field-unit module and reviewed course schedule for one selected wall system.
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Treating a field-unit count as a complete wall design
✓
Obtain separate approved schedules for geometry, specialty units, base, drainage, soil, reinforcement, loads, permits and inspection.
FAQ
Visible height alone does not establish buried courses, steps, tapers, system setback or the approved wall configuration. Enter the whole course count from the responsible plan or exact system review.
Use the exact selected product's installed horizontal module. Manufacturer dimensions, connections, setback and pattern rules vary; nominal face arithmetic is not an approved layout.
No. Those are different products with their own modules, cuts, packaging and installation requirements. Reconcile each through a separate reviewed schedule.
No. CMHA guidance makes soil, loads, geometry, groundwater, drainage and the specific unit-reinforcement system design-dependent. Obtain approved requirements and quantities separately.
Before relying on a material count, confirm the exact system instructions, site conditions, local code/permit requirements and whether responsible engineering is required. This calculator does not set a universal height threshold.
About Retaining Wall Calculator
Create an auditable purchase count for one exact standard field-unit product on a straight, constant-run segmental retaining wall. Enter the measured run, the total whole courses already established by the responsible plan or system review, the exact installed horizontal module, an explicit field-unit allowance, usable matching stock and the current supplier pack quantity. The result does not design the wall or invent caps, aggregate, drainage, reinforcement or adhesive.