# AutoCalcs

> Browser-based structural analysis software with integrated steel design checks. Build 3D finite element models, run linear, P-Delta, buckling and modal (dynamic frequency) analysis, and verify members to AISC 360-16/22, Eurocode 3, AS4100 & CSA S16.

## Key Facts

- AutoCalcs is a free, browser-based 3D structural finite element analysis (FEA) tool — no download or installation required. Free models are limited to 8 nodes, except unchanged official sample models; anonymous users receive 2 analysis runs per day and free signed-in users receive 5.
- Analysis types: linear static, P-Delta (second-order), elastic buckling (eigenvalue), and modal (natural frequency), plus tension/compression-only members.
- Loads and boundary conditions: nodal forces and moments; distributed loads, concentrated forces and moments, and thermal (temperature change and gradient) member loads; self-weight; spring supports; support settlement (prescribed displacement); member end releases; member end eccentricities; and rigid diaphragm constraints (in-plane floor/wall tying via master-slave MPC).
- Results visualisation: deflected shape, support reactions, member force diagrams (axial, shear, moment, torsion), and member stress contours from solved 1D member forces and section geometry (total, axial, and bending normal stress; torsional and total shear stress; maximum/minimum principal stress; von Mises and Tresca equivalent stress; and Rankine maximum principal tension). Member stress contours are elastic beam-theory post-processing, not local shell/solid stress analysis of web/flange junctions, support/load-introduction regions, welds, bolts, or connections. Rendered/outlined views show per-fibre quantities across the member surface; wireframe uses a station gradient. Concrete member stress contours are gross-section elastic stresses only, not reinforced-concrete stress recovery or capacity checks.
- Integrated steel design code checks to AISC 360-16 and AISC 360-22 (USA), Eurocode 3 / EN 1993-1-1 (Europe), AS 4100:2020 (Australia), and CSA S16:19 (Canada).
- Section library of 10,000+ shapes across US, European, Australian, Canadian, and UK standards; supports metric and imperial units.
- AutoCalcs uses a customized PyNite-based analysis engine. AutoCalcs-specific extensions include production plate/shell, buckling, modal, and constraint paths; public verification pages cover the FEA capabilities and listed steel design engines.
- The Custom Section Builder draws, edits, combines, and DXF-imports arbitrary cross-sections, calculates section properties, and supports section stress review, cloud saving, and reuse in Structural FEA.

## App

- [Structural FEA Tool](https://autocalcs.com/structuralfea): Launch the 3D structural analysis application
- [Custom Section Builder](https://autocalcs.com/custom-section-builder): Draw or import custom cross-sections and calculate their engineering properties

## Documentation

- [Custom Section Builder Guide](https://autocalcs.com/documentation/custom-section-builder): Draw, edit, import, calculate, save, and reuse custom structural cross-sections
- [Getting Started](https://autocalcs.com/documentation/structuralfea/getting-started): Create your first structural model step-by-step
- [Interface Overview](https://autocalcs.com/documentation/structuralfea/interface-overview): Guide to every tool, button, and control in the interface
- [Drawing](https://autocalcs.com/documentation/structuralfea/drawing): Draw structural members with snapping and coordinate input
- [Editing](https://autocalcs.com/documentation/structuralfea/editing): Undo, delete, move, intersect, and split operations
- [Selection](https://autocalcs.com/documentation/structuralfea/selection): Select objects with click, box selection, and shortcuts
- [Copy, Extrude & Mirror](https://autocalcs.com/documentation/structuralfea/copy-extrude-mirror): Duplicate geometry with copy, extrude, and mirror tools
- [Nodes](https://autocalcs.com/documentation/structuralfea/nodes): Node properties, supports, spring supports, support settlement (prescribed displacement), and degrees of freedom
- [Members](https://autocalcs.com/documentation/structuralfea/members): Member properties, sections, materials, end releases, and end eccentricities (rigid joint offsets)
- [Rigid Diaphragms](https://autocalcs.com/documentation/structuralfea/rigid-diaphragms): In-plane floor and wall constraints via a master node; phantom centroid master or existing node; integrates with seismic lateral load distribution
- [Sections](https://autocalcs.com/documentation/structuralfea/sections): Cross-section library and custom section definitions
- [Materials](https://autocalcs.com/documentation/structuralfea/materials): Material library and property definitions
- [File Management](https://autocalcs.com/documentation/structuralfea/file-management): Save, load, import/export projects with local and cloud storage
- [Load Cases](https://autocalcs.com/documentation/structuralfea/load-cases): Organise loads into named groups (dead, live, wind, etc.)
- [Node Loads](https://autocalcs.com/documentation/structuralfea/node-loads): Apply concentrated forces and moments at nodes
- [Member Loads](https://autocalcs.com/documentation/structuralfea/member-loads): Apply distributed, concentrated, and thermal (temperature change and gradient) loads to members
- [Self Weight](https://autocalcs.com/documentation/structuralfea/self-weight): Automatic gravity load calculation from section and material properties
- [Load Combinations](https://autocalcs.com/documentation/structuralfea/load-combinations): Combine load cases with factors per ASCE 7, AS/NZS 1170, Eurocode, NBCC
- [Running Analysis](https://autocalcs.com/documentation/structuralfea/running-analysis): Execute analysis, health checks, and troubleshoot common errors
- [Analysis Types](https://autocalcs.com/documentation/structuralfea/analysis-types): Linear, P-Delta (second-order), buckling, and modal (natural frequency) analysis comparison
- [Result Types](https://autocalcs.com/documentation/structuralfea/result-types): Displacement, reactions, axial, shear, moment, torsion, and member stress contours (von Mises, Tresca, Rankine, principal, and more)
- [Viewing Results](https://autocalcs.com/documentation/structuralfea/viewing-results): Visualise, scale, and read result diagrams and values
- [Sign Conventions](https://autocalcs.com/documentation/structuralfea/sign-conventions): Global and local coordinate systems, Right-Hand Rule
- [Settings](https://autocalcs.com/documentation/structuralfea/settings): Configure theme, units, hotkeys, and profile options
- [Keyboard Shortcuts](https://autocalcs.com/documentation/structuralfea/keyboard-shortcuts): Default shortcuts for tools, selection, editing, and views

## Educational Guides

- [How to Build a 3D FEA Model](https://autocalcs.com/build-3d-fea-model): Step-by-step guide from first node to viewing results
- [Linear vs Nonlinear Analysis](https://autocalcs.com/linear-vs-nonlinear-analysis): When first-order analysis is enough and when P-Delta is needed
- [P-Delta Analysis Guide](https://autocalcs.com/p-delta-analysis): Complete guide to second-order effects in structural analysis
- [Buckling Analysis Guide](https://autocalcs.com/buckling-analysis): Complete guide to eigenvalue buckling, critical load factors, and K-factors
- [Modal Analysis Guide](https://autocalcs.com/modal-analysis): Complete guide to natural frequencies, mode shapes, and mass participation for seismic design and floor vibration
- [For Students](https://autocalcs.com/for-students): Free FEA tools for learning structural analysis concepts
- [Why AutoCalcs](https://autocalcs.com/why-autocalcs): The 80/20 approach — essential features at a fraction of the cost

## Free Calculators

- [Beam Calculator](https://autocalcs.com/free-beam-calculator): Analyse simply supported, cantilever, and continuous beams
- [Frame Analysis](https://autocalcs.com/free-frame-analysis): 2D and 3D portal frame and multi-storey frame analysis
- [Plate Analysis](https://autocalcs.com/free-plate-analysis): Slab, wall, panel, and diaphragm analysis with quad and triangle shell elements
- [Truss Calculator](https://autocalcs.com/free-truss-calculator): Roof truss, bridge truss, and custom truss analysis
- [Beam Deflection Formulas](https://autocalcs.com/beam-deflection-formulas): Interactive calculator and formula reference for beam deflection
- [Moment of Inertia Calculator](https://autocalcs.com/moment-of-inertia-calculator): Second moment of area for rectangles, circles, I-beams, and hollow sections
- [Section Properties Calculator](https://autocalcs.com/section-properties-calculator): Area, I, J, section modulus, and centroid for common cross-sections
- [Von Mises Stress Calculator](https://autocalcs.com/von-mises-stress-calculator): Equivalent stress, yield utilisation, and factor of safety from 3D or plane stress
- [Principal Stress & Mohr's Circle Calculator](https://autocalcs.com/principal-stress-calculator): Principal stresses, max shear, principal angle, and drawn Mohr's circle from plane stress
- [Flat Plate Deflection & Stress Calculator](https://autocalcs.com/plate-deflection-calculator): Rectangular and circular plate deflection and bending stress under uniform or point loads
- [Beam Load Capacity Calculator](https://autocalcs.com/beam-load-capacity-calculator): Maximum allowable load based on stress and deflection limits
- [Tributary Width Calculator](https://autocalcs.com/tributary-width-calculator): Convert floor, roof, wind, or snow area loads into equivalent beam line loads
- [Load Combination Calculator](https://autocalcs.com/load-combination-generator): Check scalar load combinations for AS/NZS 1170, ASCE 7-22, Eurocode 0, and NBCC
- [Structural Unit Converter](https://autocalcs.com/structural-unit-converter): Convert between metric and imperial structural engineering units
- [Young's Modulus Calculator](https://autocalcs.com/youngs-modulus-calculator): Young's modulus values for steel, concrete, timber, and aluminium
- [Effective Length Factor Calculator](https://autocalcs.com/effective-length-factor-calculator): K-factor for columns based on end restraint conditions
- [Euler Buckling Calculator](https://autocalcs.com/column-buckling-calculator): Ideal elastic critical load Pcr for a single column with end-condition K factors
- [Embodied Carbon Calculator](https://autocalcs.com/embodied-carbon-calculator): Estimate embodied carbon (kgCO2e) for structural steel members

## Steel Design Calculators

- [AISC 360-16 Design Calculator](https://autocalcs.com/aisc-360-16-design-calculator): Steel member design check per AISC 360-16 (LRFD & ASD) — W-shapes, HSS, CHS, angles, channels, tees
- [AISC 360-22 Design Calculator](https://autocalcs.com/aisc-360-22-design-calculator): Steel member design check per AISC 360-22 (LRFD & ASD) - W-shapes, HSS, CHS, angles, channels, tees
- [EC3 Eurocode 3 Design Calculator](https://autocalcs.com/ec3-design-calculator): Steel member design check per EN 1993-1-1 — classification, resistance, buckling, LTB, combined stability
- [AS4100 Design Calculator](https://autocalcs.com/as4100-design-calculator): Steel member design check per AS 4100:2020 — UB, UC, CHS, SHS, RHS, angles, tees, channels
- [CSA S16-19 Design Calculator](https://autocalcs.com/csa-s16-design-calculator): Steel member design check per CSA S16:19 — W-shapes, HSS, CHS, angles, channels, tees

## Other

- [FAQs](https://autocalcs.com/faqs): Frequently asked questions about features, pricing, and technical details
- [Pricing](https://autocalcs.com/pricing): Free and Pro plans — monthly or annual billing
- [Full Documentation](https://autocalcs.com/llms-full.txt): Complete documentation in plain text