Concrete Stairs Calculator

Measure the rise, run, and width your plans or existing stairs already specify, and count the poured step levels as shown in the diagram. This calculator does not tell you what those numbers should be — it converts the numbers you already have into concrete volume.

Count the actual poured step levels represented in the diagram — each counted step has its own tread and the concrete beneath it, down to the base of the stair. The highest counted tread is part of the stair volume. An existing porch, floor, or landing beyond that step is not included, and this calculator does not assume one exists. This definition is specific to how this calculator models the concrete solid — it is not a claim about how architectural stair design counts risers or treads in every situation.

A solid stepped stair can be broken into as many stacked rectangular layers as it has steps: the bottom layer spans the full depth of every step above it, and each layer above spans one step's depth less than the layer below it. Summing those layers gives width × rise × run × [N(N+1) ÷ 2], where N is the number of concrete steps — the same result as adding up 1 + 2 + ... + N stacked step blocks.

This calculator models solid, mass-poured concrete steps only — the kind commonly built for a porch, entryway, or garden path. It does not model a waist-slab or suspended structural staircase (an inclined structural slab with steps formed on top of it), which is a materially different shape requiring structural inputs like waist thickness that this calculator does not ask for and cannot safely estimate without engineering input.

A landing can be a thin slab on prepared fill, a solid block, or a suspended structural element — each a different shape with a different volume model. Rather than guess which one applies to your project, this calculator estimates the solid concrete steps only. If you have a separate landing or slab pour, estimate it separately with the Concrete Slab Calculator (flatwork) or the Concrete Calculator (other shapes), and add that to this calculator's result.

Add one section per set of stairs in your project — front steps, back steps, or any other separate run. Each section's volume is calculated in full, all sections are added together at full precision, and only then is the order allowance applied once to the combined total. Nothing is rounded section-by-section along the way.

NRMCA guidance suggests roughly 4-10% over calculated volume for waste, placement, and jobsite contingencies. The 5% default is editable; adjust it for your actual project conditions.

Ready-mix concrete is delivered by truck in bulk and suits larger pours where the volume justifies a delivery. Bagged concrete mix is measured and mixed on site bag by bag, and suits smaller stair projects where a full truck delivery isn't practical. Bag counts use your product's manufacturer-stated mixed yield, never a figure guessed from bag weight.

Truck capacity is not standardized — it varies by supplier, region, and truck, so this calculator never assumes a figure. Enter the usable capacity your supplier quotes to see how many truck-capacity equivalents your order needs and how many whole truckloads to plan for. This is planning-only: it does not determine supplier minimums or delivery policies.

Use this calculator for solid concrete steps — it uses stair-specific terminology and diagrams, and combines multiple stair sections into one order.

Use the Concrete Calculator when you're combining stairs with footings, columns, walls, or other non-stair shapes in one project. Use the Concrete Slab Calculator when you have a separate slab or landing pour instead of, or in addition to, your stairs.

• Recommended rise, run, or stair width.
• Number of steps needed for a given floor-to-floor height.
• Landing dimensions or landing volume.
• Waist/slab thickness or any structural stair design.
• Reinforcement or rebar sizing.
• Structural loads, bearing, or support requirements.
• Building code or local requirement compliance.

This calculator takes dimensions you already have — from your drawings, your plans, or a professional — and converts them into concrete volume. Those design decisions belong to your project documents or a qualified professional.