# CalcTree > CalcTree is engineering calculation software that runs in the browser. Engineers write calculations with real units, inline Python and live links between pages, reuse a library of design-code templates, and publish print-ready calculation reports. Firms use it as a modern replacement for Mathcad, SMath Studio and spreadsheet calcs, mainly in structural and civil engineering. Key facts: - Web-based. Nothing to install, so it works on Windows, Mac and Linux. - Units are carried through every step of a calculation. - Python cells sit inline with the maths, with numpy, scipy and other engineering libraries pre-installed. - A page can call another page as a reusable subroutine, pinned to a revision, so verified calcs are reused rather than copied. - Template library covering Australian (AS/NZS), European (Eurocode), US (ACI, AISC, AISI) and general engineering calculations. - Real-time co-editing, comments, locking and review for designer and checker workflows. - An AI assistant builds, explains and debugs calculations. It can be switched off. - Integrations: Excel add-in (run CalcTree pages from Excel, single or batch), GraphQL API, and a skill for Claude and other LLMs. - Mathcad worksheets can be imported. - Plans: Free, Basic, Business and Enterprise. Enterprise accounts for engineering firms are priced per organisation. ## Product - [Templates](https://www.calctree.com/product/templates): Build, publish and reuse calculation templates across projects and teams. - [Parameters](https://www.calctree.com/product/parameters): Run quick iterations on calculations, designs and analysis with linked parameters. - [Projects](https://www.calctree.com/product/projects): Project-level calculation management, standardisation and quality control. - [Python](https://www.calctree.com/product/python): Fully hosted Python inside engineering calculations, with no setup. - [Spreadsheets](https://www.calctree.com/product/spreadsheets): Build calculations and templates on a spreadsheet backend. - [Excel add-in](https://www.calctree.com/product/excel): Run CalcTree pages directly from Excel, single or batch, with range linking. - [API](https://www.calctree.com/product/api): Run any calculation page with new inputs from other engineering tools. - [Pricing](https://www.calctree.com/pricing): Free, Basic, Business and Enterprise plans. ## Who it's for - [Engineers](https://www.calctree.com/solutions/engineer): Write, check and reuse calculations in one place. - [Engineering managers](https://www.calctree.com/solutions/manager): Quality control, transparency and standard calcs across projects. - [Enterprise](https://www.calctree.com/solutions/enterprise): Company-wide calculation libraries, governance and report styles for multi-disciplinary firms. - [SMEs](https://www.calctree.com/solutions/smes): Standardise calcs as a growing consultancy. - [Individuals](https://www.calctree.com/solutions/individuals): Free calculation tools for individual engineers. ## Alternatives and comparisons - [Free Mathcad alternatives in 2026](https://www.calctree.com/blog/free-mathcad-alternatives-in-2026-an-honest-review-of-the-best-options): An honest review of Mathcad alternatives, including CalcTree, SMath Studio, CalcPad, Jupyter and Excel. - [Mathcad Prime vs Mathcad 15](https://www.calctree.com/blog/mathcad-prime-vs-mathcad-15): Differences, migration problems and options for Mathcad 15 users. - [Convert Mathcad files to CalcTree](https://www.calctree.com/blog/how-to-convert-mathcad-files-to-calctree-and-actually-escape-ptc): How to move Mathcad worksheets into CalcTree. - [Can't open old Mathcad files](https://www.calctree.com/blog/cant-open-old-mathcad-files): What to do with legacy Mathcad worksheets. - [SMath Studio alternatives](https://www.calctree.com/blog/smath-studio-alternatives): Options for teams moving off SMath Studio. - [Tekla Tedds alternatives](https://www.calctree.com/blog/tekla-tedds-alternatives): Alternatives to Tedds for structural calculation packages. - [Engineering calculations online vs spreadsheets](https://www.calctree.com/blog/engineering-calculations-online-vs-spreadsheets): When to move calcs out of Excel. - [Python and handcalcs for engineering calculations](https://www.calctree.com/blog/python-handcalcs-engineering-calculations): Python-based calcs, and how CalcTree adds units, reports and sharing. ## Calculation templates: Australia (AS/NZS) - [Timber Beam Design to AS 1720.1:2010](https://www.calctree.com/templates/timber-beam-as) - [Concrete Beam Design to AS 3600](https://www.calctree.com/templates/concrete-beam-as) - [Concrete Column Design to AS 3600](https://www.calctree.com/templates/concrete-column-as) - [Reinforcement Development Length to AS 3600-2018](https://www.calctree.com/templates/development-length) - [Neutral Axis of an RC Section to AS 3600:2018](https://www.calctree.com/templates/neutral-axis-as) - [Bolt Group Calculator to AS 4100-2020](https://www.calctree.com/templates/bolt-group) - [Fillet Weld Group Analysis to AS 4100-2020](https://www.calctree.com/templates/weld-group) ## Calculation templates: Europe (Eurocode) - [Timber Beam Design to Eurocode 5](https://www.calctree.com/templates/timber-beam) - [Timber Bending Check to EC5 (Cl 5.2.1.1)](https://www.calctree.com/templates/timber-bending-check-ec5) - [Timber Shear Check to EC5 (Cl 5.2.1.2)](https://www.calctree.com/templates/timber-shear-check-ec5) - [Timber Bearing Check to EC5 (Cl 5.2.1.3)](https://www.calctree.com/templates/timber-bearing-check-ec5) - [Timber Deflection Check to EC5 (Table 7.2)](https://www.calctree.com/templates/timber-deflection-check-ec5) - [Steel Base Plate Calculator to Eurocode 3](https://www.calctree.com/templates/baseplate-ec3) ## Calculation templates: United States (ACI, AISC, AISI) - [Concrete Rectangular Beam Design to ACI 318-19](https://www.calctree.com/templates/concrete-beam) - [Concrete Column Design to ACI 318-19](https://www.calctree.com/templates/concrete-column) - [RC Column P-M Interaction Diagram Generator](https://www.calctree.com/templates/interaction-diagram-generator) - [Concrete Slab-on-Grade Design to ACI 360R-10](https://www.calctree.com/templates/slab-on-grade-aci) - [ACI 318-19 Two-Way Shear (vc)](https://www.calctree.com/templates/aci-318-two-way-shear-vc) - [ACI 318-19 In-Plane Shear Strength of Structural Walls](https://www.calctree.com/templates/aci-318-19-wall-shear) - [ACI 318-19 Minimum Slab Thickness, One-Way Slabs](https://www.calctree.com/templates/aci-318-19-one-way-slab-thickness) - [ACI 318-19 Torsional Strength](https://www.calctree.com/templates/aci-318-19-torsional-strength) - [Allowable Steel Beam End Reaction to AISC](https://www.calctree.com/templates/end-reaction) - [Steel Purlins and Girts to AISI](https://www.calctree.com/templates/purlin-girt) - [All calculation templates](https://www.calctree.com/templates): The full library, including 60+ ACI 318-19 clause checks. ## Calculation templates: general - [Beam Analysis using Macaulay's Method](https://www.calctree.com/templates/macaulay) - [Bearing Capacity of Shallow Footings (Terzaghi)](https://www.calctree.com/templates/terzaghi) - [Moment of Inertia: Rectangular Hollow Sections](https://www.calctree.com/templates/inertia-moment-shs) - [Moment of Inertia: Circular Hollow Section](https://www.calctree.com/templates/moment-inertia-chs) - [Moment of Inertia: Angle Section](https://www.calctree.com/templates/moment-inertia-angle) - [Reinforced concrete section analysis (concreteproperties)](https://www.calctree.com/templates/concreteproperties) - [Steel member checks with steelpy](https://www.calctree.com/templates/steelpy) ## Engineering guides - [Timber design to AS 1720 and AS 1684](https://www.calctree.com/resources/timber-as) - [Timber design to NDS](https://www.calctree.com/resources/timber-nds) - [Concrete beam design to AS 3600](https://www.calctree.com/resources/concrete-beam-as) - [Concrete slab design to AS 3600](https://www.calctree.com/resources/concrete-slab-as) - [Shear wall design to AS 3600](https://www.calctree.com/resources/shear-wall-as) - [Slab-on-grade design to ACI](https://www.calctree.com/resources/slab-grade-aci) - [Steel base plate design to AISC](https://www.calctree.com/resources/baseplate-aisc) - [Steel base plate design to Eurocode 3](https://www.calctree.com/resources/baseplate-ec3) - [Bolt group design to AS 4100](https://www.calctree.com/resources/bolt-group-as) - [Weld group design to AS 4100](https://www.calctree.com/resources/weld-group-as) - [Wind loads to ASCE 7](https://www.calctree.com/resources/wind-asce) - [Moment of inertia](https://www.calctree.com/resources/moment-inertia) - [Soil bearing capacity](https://www.calctree.com/resources/bearing) - [Truss design](https://www.calctree.com/resources/truss) - [Calculation verification process](https://www.calctree.com/resources/calculation-verification-process) - [Calculation template guide](https://www.calctree.com/resources/calculation-template-guide) - [All engineering guides](https://www.calctree.com/resources) ## Docs and integrations - [Guides and support](https://calctree.gitbook.io/docs): How to use CalcTree. - [GraphQL API docs](https://calctree.gitbook.io/docs/api/graphql-api): Build apps and integrations on top of CalcTree. - [CalcTree skill for Claude and other LLMs](https://www.calctree.com/blog/calctree-llm-skill): Run and build CalcTree calculations from an AI assistant. - [CalcTree for Excel](https://www.calctree.com/blog/calctree-for-excel): Run calculation pages from Excel. - [CalcTree AI](https://www.calctree.com/blog/calctree-ai-a-new-way-to-build-extend-and-review-engineering-calculations): Build, extend and review engineering calculations with AI. ## Company - [About](https://www.calctree.com/about): Modern calculation tooling for the people who build our world. - [Privacy and security](https://www.calctree.com/blog/privacy-security): How CalcTree protects engineering IP. - [Book a call](https://www.calctree.com/book-a-call) - [Request a template](https://www.calctree.com/request-a-template) ## Optional - [Blog](https://www.calctree.com/blog): Product updates, engineering workflows and opinion. - [Product roadmap](https://calctree.productlane.com/roadmap): Upcoming features.