Calcpad — The Complete Guide: Free Engineering Calculation Sheets with Units

Calcpad is open-source software (MIT licence) from Proektsoft for writing engineering calculation sheets. You type variables and formulas as plain text, with units, and it produces a readable report showing the formula, the substituted numbers and the result — like a tidy hand calculation for a checker. It runs on Windows, and there is also a version that works in the browser.

Calcpad

Proektsoft EOOD

Engineering calculation sheets: write formulas with units in plain text and get a formatted calculation report. A free Mathcad alternative.

Get it from the vendor

What you get

Units — automatic conversion and consistency checks between kN, m, MPa and so on.
Transparent report — every line shown with formula, substitution and result.
Logic — conditions and loops, for example checking whether utilisation exceeds 1.0.
Plots and tables — functions and results displayed inside the sheet.
Templates — a sheet written once is reused with new input data.

How engineers use it

Structural engineers build a personal library of recurring checks — beam, column, bolt, weld, base plate — and change only the inputs on each project. The file is plain text, so it is easy to keep under version control and compare revisions. It is not a replacement for structural analysis software: the forces come from your model, and Calcpad documents the check.

Related tools

For a graphical editor in the Mathcad style — SMath Studio. For the free edition of the original — Mathcad Express. For calculation reports generated from Python code — handcalcs.