About GAUGE

A precision engineering unit converter built for accuracy.

GAUGE is a free online unit converter spanning 383 units across 34 measurement categories — length, mass, pressure, energy, power, torque, flow, density, electrical, magnetic, radiation, and more. It was built for engineers, machinists, scientists, students, and anyone who needs a conversion they can trust.

Why another converter?

Most converters cover the common handful of units and stop there. GAUGE goes deep: alongside everyday conversions it includes specialist units that are hard to find elsewhere, such as French gauge (Charrière) for tubing and catheters, circular mils for wire cross-sections, dynamic and kinematic viscosity, magnetic flux density, and radiation dose.

Accuracy first

Every conversion factor is derived from internationally recognized SI definitions and published standards. Conversions are computed by a single, audited calculation engine and round-trip tested, so converting A→B and back returns the original value. Temperature and fuel-economy conversions use exact formulas rather than simple multipliers.

Smart Convert

The Smart Convert box lets you type a conversion in plain English — for example, "5 french to inches" or "how many mm in 2 inch". A natural-language layer interprets your request and identifies the units, but the actual arithmetic is always performed by the verified engine. The number is computed, never guessed — which is what keeps it reliable.

GAUGE is provided as a free reference tool. While we work hard to keep it accurate, you should independently verify results before relying on them for safety-critical, regulatory, or commercial decisions. See our Terms of Use.

Contact

Questions, corrections, or unit requests are welcome — visit the contact page.