Write the calculation the way you would on paper. Units are real, results are live, and the checks say pass or fail.
Coming from Mathcad? Convert a worksheet in your browser: most of it converts, and the report lists what did not. The file is never uploaded.
One sheet holds the working, the units, the checks and the pictures, and it reads like a calculation a colleague would hand you.
Every quantity carries its unit. A stress times a section modulus comes out in kN·m, and mixed units convert without a table of factors.
Markdown prose, name: value unit | note lines and checks, with LaTeX where you want a typeset formula. A sheet diffs and versions like code.
Interactive 2D and 3D charts: a plate deflection surface, an interaction diagram, a frame in 3D. Drag to rotate.
Run Python blocks in the page for the awkward parts, and send results back into the sheet to check against a limit.
Simplify, expand, factor, differentiate and integrate, then insert the typeset result into the sheet.
Write a flowchart, a Gantt chart, a Sankey or a state diagram as text in the sheet, and the results draw it.
Import Mathcad .xmcd and .mcdx worksheets with a report of what did not convert. Calcpad worksheets open as they are.
Export to PDF, Word, Excel or standalone HTML, with the calculations and charts as you see them.
Fill in a form instead of editing: number boxes and sliders, with the results and checks updating live.
Install it from the browser on a phone or desktop. It opens and calculates without a connection, and your sheets stay on your device.
On a narrow screen the ribbon, editor and results rearrange to fit, so a sheet is readable and editable away from the desk.
MIT licensed and built on the CalcpadCE engine, rewritten in Rust and WebAssembly.
Ag: 7.5e3 mm² | gross area fy: 350 MPa | yield strength Nstar: 1200 kN | design axial load Nc: Ag * fy -> kN | squash load phiN: 0.85 * 0.8 * Nc -> kN if Nstar / phiN <= 1: "OK" else: "Fails"
Ready-made calculations that open in Calcs, and short guides for engineers coming from other tools. See all calculators and guides.
Moment, shear, bending stress and deflection of an I-beam under a uniform load.
Bearing pressure under a column load and moment, with eccentricity and uplift.
Earth thrust, overturning and sliding safety factors and base pressure.
Velocity, Reynolds number, friction factor, head loss and pump power.
Where the pump curve meets the system curve, with both curves plotted.
Templates for beams, walls, footings, pipes and pumps, with exports.
Real units, plots, exports and offline use, with a worksheet importer.
What converts from .xmcd and .mcdx, and why your file is not uploaded.
Readable formulas with units instead of cell references, and the workings shown.
Run Calcpad worksheets in a browser on a Rust engine compiled to WebAssembly.
Put a calculator on your own page, or let an AI assistant run and check calculations with the same engine.
Add a live calculator to any page with one iframe. No account, no script to install.
CivilKit<iframe src="https://civilkit.io/calcs/?embed=1&sample=template-simply-supported-beam"
width="100%" height="640" title="Simply supported beam"></iframe>A public, read-only MCP server lets an assistant run sheets, check a hand calculation against the engine and search the guide. Nothing is stored.
claude mcp add --transport http civilkit-calcs https://civilkit.io/mcp