Calculators and guides
CivilKit Calcs is a free calculation sheet for engineers that runs in your browser and keeps working offline. These pages show what it does on real problems: calculators that open as fill-in forms, notes for people coming from another tool, and short guides. Every number quoted on them comes from a run of the engine.
Open Calcs Read the user guide
Calculators
Each calculator is a sheet that opens in the app as a form, with a worked example whose numbers come from the engine. They are generic textbook calculations, not design-code checks.
Structural
- Simply supported beam: Free beam calculator: moment, shear, bending stress and deflection of a simply supported I-beam under a uniform load, with a moment diagram. Opens as a form.
- Cantilever beam: Free cantilever calculator with units: moment, shear, bending stress, tip deflection and rotation for a point load at the free end, with a moment diagram.
- Column buckling: Slenderness and buckling of a solid rectangular column: end conditions, the Euler or parabolic critical stress and the allowed load, as a form you can edit.
- Moment and shear diagrams: Plot bending moment and shear force along a simply supported beam from a moment function, worked out at sixths of the span in a loop, with real units.
- Principal stresses: Principal stresses and directions of a plane or 3D stress tensor from eigenvalues and eigenvectors, checked against Mohr's circle, with units.
- Principal axes of a section: Strong and weak axes of an unsymmetric cross-section from the second moments of area by eigenvalues, checked against the closed-form result.
- Shear frame frequencies: Natural frequencies and mode shapes of a two storey shear frame from the generalised eigenvalue problem K phi = w^2 M phi, worked with units.
- Gable frame thrust: Horizontal thrust of a symmetric pitched roof frame for a pinned ridge and a rigid ridge, and why the common shortcut overstates it.
Geotechnical
- Retaining wall stability: Free retaining wall calculator: active earth thrust, overturning and sliding safety factors and base pressure for a cantilever wall, with units.
- Pad footing bearing pressure: Free pad footing calculator: bearing pressure under a column load and moment, eccentricity, uplift and the check against an allowable soil pressure.
Hydraulics
- Pipe flow, Darcy-Weisbach: Free pipe friction loss calculator: velocity, Reynolds number, friction factor, Darcy-Weisbach head loss, pump head and power for water in a full pipe.
- Pump operating point: Free calculator for the operating point of a pump on a pipeline: where the pump curve meets the system curve, with a table of heads and both curves plotted.
Materials
- Concrete strength gain: Strength of concrete at ages from 1 to 28 days from a common strength gain formula, listed on a timeline and plotted. Edit the 28-day strength.
Alternatives and migration
For engineers comparing tools, or bringing worksheets across from another one.
- Mathcad alternative: A free, open source engineering calculation sheet for the browser: real units, plots, Word and Excel export, offline use, and a Mathcad worksheet importer.
- Calcpad worksheets in the browser: Open and run Calcpad .cpd worksheets in your browser, offline, on an open source Rust engine. Edit, plot, import and export to Word, Excel or PDF.
- Excel alternative: Write engineering calculations with units and readable formulas instead of cell references, see the workings, and export to Word, PDF and Excel.
- Free calculation software: A free browser tool for engineering calculations with units: templates for beams, walls, footings, pipes and pumps, plots, and Word, Excel and PDF export.
- Open Mathcad files: Open Mathcad .xmcd and .mcdx worksheets without Mathcad: they convert to a live calculation sheet in your browser, and nothing is uploaded.
Guides
How-to pages on what a calculation sheet can do. The full manual is the user guide, and every release is on What's new.
- Beam deflection formula, derived: Derive the midspan deflection of a simply supported beam under a uniform load step by step with symbolic integration, then check it against a plotted curve.
- Export to Word, Excel and PDF: Turn a calculation into a Word report with real equations, an Excel workbook with native charts, or a PDF, from the browser. What each format keeps.
- Calculations with units: Write calculations where every quantity carries a unit: SI and US customary units, prefixes, unit errors that catch mistakes, and your own units.
Quick reference
The sheet language on one printable page: every line kind, input, function, constant and unit. See the quick reference.
Embed a calculator
The calculators can also live on your own site: a free, copy and paste frame that calculates in the reader's browser. See Embed a calculator.