About CivilStrCalc

Free structural engineering calculators — open to everyone, no registration required.

What is CivilStrCalc?

CivilStrCalc is a free, browser-based toolkit for structural engineers, students, and educators working with reinforced concrete and structural steel. Every calculation runs entirely in your browser — no data is sent to any server, no account is needed, and there are no paywalls.

The tools implement the full provisions of the most widely used design standards: ACI 318-25 (United States), Eurocode 2 EN 1992-1-1 (Europe), and IS 456:2000 (India). Each result comes with a step-by-step calculation report that can be printed or saved as a PDF.

What Can You Calculate?

Beam Design — Flexural design and capacity, shear design (stirrups), and torsion design for rectangular and T-section RC beams.
Slab Design — One-way flexural design and punching shear checks for flat-plate systems. Covers interior, edge, and corner columns with stud rail (SSR) and radial ring reinforcement options.
Column Design — P-M_x-M_y interaction diagram for rectangular and circular columns under combined axial load and biaxial bending. Includes transverse reinforcement sizing and seismic confinement checks.
Steel Section Tables — Searchable database of IPE, HEA/B/M, W, HSS, ISMB, ISMC, and other standard profiles per EN 10365, AISC, and IS 808, with a custom section calculator.
Rebar Properties — Bar sizes and mechanical properties for ASTM A615/A706, EN 10080 B400/B500, and IS 1786 Fe415–Fe600 grades.
Concrete Classes — Design properties (f_ck, f_cd, E_cm, strain limits) for all standard strength classes per Eurocode 2, ACI 318, and IS 456:2000.

Who Is It For?

CivilStrCalc is designed for anyone working with structural concrete or steel:

Practising engineers who need quick, reliable preliminary calculations before moving to full analysis software.
Students studying structural engineering who want to verify hand calculations or explore how code provisions work in practice.
Educators looking for a free classroom tool that shows every calculation step transparently.
Checkers and reviewers who need an independent calculation to cross-check design outputs.

Design Philosophy

Every intermediate step is shown. We believe structural engineering software should be a transparent aid to engineering judgement — not a black box. If you cannot follow every step in the report, the result should not be trusted.

All calculations are client-side: your inputs never leave your device. The tools work offline once the page is loaded, and there is no tracking of individual calculation inputs.

Standards and References

ACI 318-25 — Building Code Requirements for Structural Concrete
EN 1992-1-1:2004 (Eurocode 2) — Design of Concrete Structures
IS 456:2000 — Plain and Reinforced Concrete Code of Practice
EN 10365:2017 — Hot Rolled Steel Sections
AISC Steel Construction Manual (16th Edition)
IS 808:1989 — Dimensions for Hot Rolled Steel Sections
ASTM A615/A706, EN 10080, IS 1786 — Reinforcing Steel

Disclaimer

CivilStrCalc is intended for educational and preliminary design purposes only. All results must be independently verified by a licensed structural engineer before use in any construction project. The site makes no warranty as to the accuracy or fitness for purpose of any calculation result. See our Terms of Use for full details.

Contact

Questions, error reports, or suggestions are welcome at info@civilstrcalc.com.