Enter each specified tier as a row, identify its product and separate body units from finish pieces. The material table keeps supporting blockwork, tread pieces and caps visible as distinct order lines, including blocks hidden beneath or behind the visible risers.
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How this calculator works
Structured rows multiply units per course by courses and identical repeats. Lines are grouped by stock product and body or finish role, with each product allowance rounded separately. Quick list mode sums the supplied tier quantities. A fully filled rectangular tier model uses units across × units per tread × courses per rise × tiers × (tiers + 1) ÷ 2. Body unit allowance is applied after counting.
This estimates the body and finish unit quantities in your supplied schedule or selected tier model. It does not design stair dimensions, support, foundations, treads, caps, handrails or code compliance.
Start with the full step arrangement
A stair can use block risers, a filled backing, solid block tiers or another documented system. Two stairs with the same exposed width and number of risers can need very different quantities. Start with the product and arrangement shown in the project detail.
The tier schedule gives each line a name and product, then records its units per course, number of courses and identical repeats. Use separate rows for support courses, side returns or a landing when the detail calls for them. A visible front row is only part of the quantity if there are supporting blocks behind it.
The calculator counts the arrangement you supply. It does not choose rise, run, footing dimensions, support, reinforcement, guardrails or other stair design requirements.
Keep the material system specific
Segmental retaining wall stair details can use wall rock below and behind successive risers, with capstones or pavers providing the tread finish. Allan Block publishes examples of this approach for its products.
That does not mean the same block count or support method applies to mortared CMU steps. A concrete masonry step detail can require different unit types, mortar, grout and support. Select the product and arrangement first, then record its quantities.
The finish also matters. A paver tread, a manufactured cap and a poured concrete tread have different dimensions and order units. The block schedule alone does not purchase those surfaces.
Count each tier, course and product type
Base units on one row = units per course × courses × repeated identical arrangements. For example, eight units in two courses repeated twice gives 8 × 2 × 2 = 32 units on that row.
Select body for supporting or riser blockwork. Select finish for separate tread pieces or caps. Use the same product identifier on rows that describe the same order item. Keep a different size, shape, finish or left and right product on a separate line.
The material table adds matching products before applying their relevant allowance. Product order = base units for that product × (1 + allowance ÷ 100), rounded up. Body and finish allowances are separate so an allowance for cut supporting blocks is not silently applied to every tread.
Round each actual product order separately. Twenty small offcuts do not automatically replace twenty full units, and an offcut is reusable only when its dimensions and suitability match another specified piece.
Worked example: three body tiers and a separate finish order
Suppose an existing detail supplies 24 body units at Tier A, 16 at Tier B and eight at Tier C. Each example row uses one course and one repeat. These are supplied quantities for arithmetic, not a suggested stair layout.
| Row | Units per course | Courses | Repeats | Base units |
|---|---|---|---|---|
| Tier A | 24 | 1 | 1 | 24 |
| Tier B | 16 | 1 | 1 | 16 |
| Tier C | 8 | 1 | 1 | 8 |
The base quantity is 24 + 16 + 8 = 48 body units. A chosen 5% body allowance produces 50.4, rounded up to 51 stock units of that product. If Tier A actually contains two courses, change its course entry to two; its row becomes 48 and the combined base quantity becomes 72.
For a separate example finish, suppose the finish layout specifies 12 tread pieces. At a chosen 10% finish allowance, that product needs 12 × 1.10 = 13.2, rounded up to 14 pieces. The body order remains 51. A finish quantity of zero excludes that item until its layout is supplied.
Choose the schedule or the rectangular tier model
The tier schedule is the most flexible option for a supplied detail. It can hold different products, support rows and repeated arrangements without assuming that every staircase is a solid block stack. The simple quantity list remains useful for an existing total that has already been worked out.
The rectangular tier model is a separate arithmetic model. It assumes equal modules, a uniform width and fully filled successive rectangular tiers. Its body count is units across × units per tread × courses per rise × number of tiers × (number of tiers + 1) ÷ 2.
With two units across, one unit per tread module, one course per rise and three equal tiers, the model contains 2 × 1 × 1 × 3 × 4 ÷ 2 = 12 body units before allowance. This does not describe a design with aggregate backing, hollow support regions or a landing. Use the supplied schedule for those cases.
Add treads, caps, support and fill deliberately
| Component | Quantity source |
|---|---|
| Riser and support units | Supplied tier and course schedule |
| Tread or cap pieces | Finish layout and effective product dimensions |
| Landing and side returns | Separate plan areas and unit schedule |
| Aggregate or concrete backing | Specified material regions and dimensions |
| Mortar, grout and reinforcement | Specified masonry detail and product yields |
| Foundation | Specified foundation geometry and material |
Do not count the same support volume twice. An aggregate backing region is not automatically a solid region of concrete blocks. Hollow block fill is also different from the outer volume occupied by the units.
For specified poured concrete foundation dimensions, use the footing volume calculator. Use the fill calculator only with documented void volumes and the selected fill product.
Use the block layout calculator for a supported wall face with positioned openings, rather than treating its wall diagram as a stair section. The wall material cost tool can help price entered masonry quantities, but a complete stair quote also needs its separate finishes, support, installation and project charges.
Check the schedule before buying materials
- Match the actual product and block orientation to the step detail.
- Count hidden supporting rows and all courses below each tier.
- Include side returns and landings as their own schedule lines.
- Separate cut pieces, specialty units, caps and treads by product.
- Confirm fill regions, foundation materials and any prescribed reinforcement.
- Keep the stock allowance visible beside the required quantity.
The material list helps check an already specified project. Stair geometry, safe use, support and applicable requirements need confirmation through the appropriate project detail and local review. The block size guide can help verify unit dimensions before you enter the schedule.
Common questions
Can I calculate concrete block steps from total height alone?
No. Total height does not reveal tread depth, supporting rows, landings, side returns or the selected product arrangement. Enter the supplied tier and course schedule.
Should I count the blocks hidden under the steps?
Yes, when the project detail calls for them. The schedule must include all supporting block rows and courses. Some systems use aggregate or another backing material instead, so follow the actual detail.
Does this choose the rise and run of my stairs?
No. The tool adds material quantities for an existing arrangement. Stair dimensions, support, foundations and applicable requirements are separate design decisions.
Are caps and tread pieces included in the block count?
Add them as finish rows with their own product identifiers and finish allowance. They appear separately from body units in the material table. Enter the quantities from the actual finish layout; the tool does not infer them from body block count.
Can I apply an Allan Block stair example to ordinary cinder blocks?
No. Manufacturer stair examples use their own units, backing and finishing details. A mortared CMU step arrangement needs its own specified material schedule and support detail.
Why should two different block products be rounded separately?
Each product is a separate purchase item. Add the base quantities for the matching product, apply its relevant allowance and round that order up. Rounding one combined total can leave a specific corner, tread or other unit short.
Sources and product references
Named product references support the examples. Confirm the currently supplied dimensions, yields and purchasing conditions before ordering.
- Allan Block retaining wall steps and stairsPrimary examples of a product specific segmental stair system with backing material and separate tread finishes. These are not generic CMU construction details.
- Allan Block commercial stair constructionProduct specific stair layout context. This calculator uses the user's supplied quantity schedule and does not select stair geometry.
- Allan Block Commercial Retaining Wall ManualThe manufacturer manual includes a material estimate worksheet, separate wall materials and buried block quantities. Use specified project geometry and local product dimensions. This reference supplies no example prices. Manufacturer reference for product dimensions, material quantities and separate wall components. Confirm the locally supplied system.