Cantilever Retaining Wall module
Free Cantilever Retaining Wall Calculator — ACI 318-25 and IBC 2024
Design cantilever concrete retaining walls per ACI 318-25, IBC 2024 and ASCE 7-22. Overturning and sliding stability (IBC 1807.2.3), soil bearing, stem/heel/toe and shear-key strength design, and reinforcement development — with IBC Table 1610.1, ASCE Table 3.2-1 or a geotechnical equivalent fluid pressure, sloped backfill, seismic earth pressure (Mononobe-Okabe, Seed-Whitman or the report's own ΔPAE), groundwater, a footing behind the wall, wind on the stem and on a fence, a stepped stem, and a stem of solid-grouted concrete masonry (CMU) designed by TMS 402-22 allowable stress design on the same concrete footing.
Free to use with no sign-up: the calculator runs in full in the browser with no account, no trial and no feature limits, and the full detailed calculation is shown on screen, step by step, with the code sections and tables it draws on, so it can be checked by hand. A free account keeps one project in the cloud; unlimited cloud projects and printing the report to PDF are Pro features.
What the calculator includes
- Every load a site puts on the wall: earth pressure from IBC Table 1610.1, ASCE 7-22 Table 3.2-1 or the geotechnical report, sloped backfill, surcharges, a footing behind the wall, groundwater, wind on the stem and on a fence on top, an axial load on the stem, and seismic earth pressure.
- Lateral pressure from IBC Table 1610.1 or ASCE 7-22 Table 3.2-1, both rendered verbatim with their footnotes, or the geotechnical report's equivalent fluid pressure; active or at-rest; sloped backfill with the rise over the heel counted.
- Surcharges as the code classes them: a uniform surcharge marked variable or permanent, a footing behind the wall as a Boussinesq strip load, and an axial roof, floor or snow load on the stem with its eccentricity.
- Groundwater with buoyant earth pressure, hydrostatic pressure and base uplift; IBC Table 1806.2 presumptive soil values; passive resistance with a disregarded depth and usable percentage; cohesion capped per IBC §1806.3.2.
- Wind on the exposed stem and on a fence or guardrail on top of the wall, with the moment reversal checked against the toe-face bars.
- Seismic earth pressure by Mononobe-Okabe, Seed-Whitman or the geotechnical report's own ΔPAE, with kh = SDS/2.5 for a yielding wall or the report's own kh, optional wall inertia, and FS ≥ 1.1 overturning and sliding at 0.7E.
- A stem stepped once on the toe face and checked at the base and at the step with the §7.7.3 bar-cutoff rules; property-line walls with no toe or no heel; a shear key placed anywhere along the footing.
- A stem of solid-grouted concrete masonry (CMU) — 6, 8, 10 or 12 in block, bars at a cell spacing — designed by TMS 402-22 Chapter 8 allowable stress design on the same concrete footing: masonry and steel stresses with the axial load, shear, the dowel lap and the Chapter 7 minimums by SDC.
- Overturning and sliding FS ≥ 1.5 per IBC §1807.2.3, kern-aware bearing, stem flexure and shear as a wall under axial load, heel, toe and key design, development lengths, laps and minimum steel per ACI 318-25, each check opening to its substituted derivation.
- A pressure diagram and a free body with every resultant and its lever arm for each load case and combination, the governing case flagged, plus a CAD-style reinforcement detail drawn to scale from the engine's own bar lengths, hooks and laps.
In every StructSuite module
- The code clause behind a value is quoted verbatim beside it from a blue book icon — NDS 2024, SDPWS 2021, AISC 360-22, ACI 318-25, ASCE 7-22 and the 2024 IBC, FEMA P-750 and the I-joist manufacturer's technical bulletins — so the standard does not have to be opened to check it.
- A missing input stops the calculation rather than being filled in silently, and judgment choices start unselected.
- Where a limit applies it is checked as you type: beam RB and column ℓe/d, steel Lc/r, rebar ratios and spacing, fy and f′c.
- Every module prints into one calculation report (Pro) with a cover sheet, a table of contents with measured page numbers and a verification link a plan checker opens without an account.
Worked examples and guides for this module
Each guide works the method end to end on the numbers the engine produces. The sample calculation report (PDF) is a complete StructSuite report printed from the sample project — open it without an account.
Frequently asked questions
What kind of retaining wall does it design?
Cantilever retaining walls on a reinforced concrete footing, with a stem of either reinforced concrete (ACI 318-25) or solid-grouted concrete masonry (TMS 402-22 allowable stress design), per IBC 2024 and ASCE 7-22: overturning and sliding stability per IBC 1807.2.3, soil bearing, strength design of the stem, heel, toe and shear key, and reinforcement development. Segmental block and mechanically stabilized earth walls are not covered.
Does it handle sloped backfill and seismic earth pressure?
Yes. Lateral pressure can come from IBC Table 1610.1, ASCE 7-22 Table 3.2-1 or a geotechnical equivalent fluid pressure, with sloped backfill, and the seismic increment can follow Mononobe-Okabe, Seed-Whitman or the geotechnical report's own ΔPAE.
Which checks does it run?
Overturning and sliding with FS ≥ 1.5 per IBC 2024 §1807.2.3, kern-aware soil bearing, stem flexure and shear at the base and at any step (as a wall under axial load, with the ACI 318-25 §6.6.4.5 moment magnifier), heel, toe and shear-key strength, hooked and straight development lengths, laps and minimum steel. With seismic on, the ΔPAE derivation, FS ≥ 1.1 overturning and sliding at 0.7E, seismic bearing and the strength combinations of ASCE 7-22 §2.3.6 are added. Every check opens to its substituted derivation with the code references. With a concrete masonry (CMU) stem the stem checks follow TMS 402-22 Chapter 8 allowable stress design instead: masonry and steel stresses on the cracked section with the axial load, the axial capacity Pa, shear, the dowel lap of Eq. 6-2 and the Chapter 7 prescriptive reinforcement by Seismic Design Category, while the footing stays ACI 318-25.
Is the cantilever retaining wall calculator free?
Yes. Free to use with no sign-up: the calculator runs in full in the browser with no account, no trial and no feature limits, and the full detailed calculation is shown on screen, step by step, with the code sections and tables it draws on, so it can be checked by hand. A free account keeps one project in the cloud; unlimited cloud projects and printing the report to PDF are Pro features.