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MachineCalcs

About & methodology

MachineCalcs is a free, independent collection of machine-design calculators for working engineers, machinists and technical makers. Every tool is built to be the actual design calculation — not a textbook widget — and to show the formula and the source behind every number. We don’t sell springs, cylinders or gears, so there’s no product to steer you toward.

How the math is done

Each calculator implements standard, published engineering formulas, computed in the browser from your inputs. The same code runs when the page is built and when you change a value, so the worked example you see on load is produced by the exact calculation you then use — there is no separate “marketing” number. Where a result depends on a convention (spring end type, gear tooth system, cylinder efficiency), we state the assumption next to the result.

  • Springs follow standard helical-spring design practice (spring rate, Wahl stress correction, solid height, and the slenderness buckling criterion).
  • Hydraulics use the pressure-times-area force relations, with the rod-area differential between push and pull shown explicitly.
  • Gears use standard full-depth involute geometry, including the inverse-involute solution for profile-shifted center distance.

Where the data comes from

The embedded reference tables — spring-wire material properties, standard cylinder bores, preferred gear modules — are compiled from recognised engineering references and standards (ASTM wire standards, ISO 6020-2, ISO 54, and standard design handbooks such as Shigley’s Mechanical Engineering Design). Each table cites its source on the page. The constants the calculator uses are the same ones shown in the table, so what you read is what is computed.

Limitations & safety

These are reference tools. They use typical published values and simplifying assumptions (for example, static loading for springs, and theoretical force for cylinders). They are not a substitute for a qualified engineer’s review on safety-critical or load-bearing designs. For production work, verify every value against the governing standard and your supplier’s certified data, and have the design reviewed by a professional engineer. We document each tool’s assumptions in its “Method & assumptions” section.

Corrections

Found a value or formula you’d question? That’s the most useful thing you can send us — accuracy is the whole point. Email hello@machinecalcs.com with the tool and the reference, and we’ll review and correct it.

Last reviewed: May 29, 2026.