Measurement guide
Unit systems covered by these converters
A practical map of the measurement systems represented in the current converter catalog, from everyday metric and US customary units to engineering, electrical, radiology, digital, and publishing units.
How this catalog works
Each converter uses a reference unit (usually an SI/metric unit) and converts all other units through it. This keeps calculations consistent and avoids unnecessary complexity.
The catalog isn't limited to metric units. It also includes imperial, US customary, CGS, and other domain-specific units (like digital, typography, lumber, or radiology) that people still use in practice.
75
converters currently registered
9
converter groups in the top navigation
77
catalog links highlighted in this guide
1681
units across all converters
Unit system
SI, metric, and decimal prefixes
Most converters use an SI or metric base so every other unit can be mapped through one dependable reference layer. That matters for scientific quantities, engineering calculations, electric units, radiology, light, heat, and everyday length or mass conversions.
Unit system
US customary and imperial everyday units
Several common converters bridge metric values with inch-pound systems used in recipes, construction, transportation, land area, body weight, fuel use, and general commerce. The important detail is that similar names can hide different definitions, especially with volume and dry volume.
Unit system
Engineering and mechanical systems
Engineering converters combine SI units with practical legacy units used in mechanics, motion, material properties, fluids, and rotational dynamics. These pages are useful when specifications mix newtons, pounds-force, pascals, poise, density units, and angular motion.
Unit system
Heat transfer and thermodynamics
Heat transfer converters cover the full range of thermal quantities used in engineering, materials science, and HVAC: temperature differences, expansion coefficients, resistance values, capacity, flux, and conductivity.
Unit system
Fluid dynamics and flow
Flow converters handle volumetric, mass, and molar flow rates alongside mass flux density - quantities used in pipe sizing, chemical processes, HVAC systems, and fluid mechanics calculations.
Unit system
Electrical, magnetic, and electromagnetic units
Electrical and magnetic converters connect SI units with CGS, practical circuit units, field-strength units, charge-density units, and specialized electromagnetic relationships. This is where volts, ohms, siemens, farads, henries, webers, teslas, gauss, and oersted live together.
Unit system
Light, radiation, and scientific reference units
The catalog also includes measurement systems that are tied to laboratory, medical, safety, and optical work. These converters often combine SI units with accepted non-SI units, historic units, and domain-specific names that remain common in documentation.
Unit system
Digital, typography, and publishing units
Not every converter is physical in the same way as length or mass. Data transfer, storage, image resolution, and typography converters cover conventions built around bits, bytes, dots, pixels, points, picas, twips, and print-oriented measurements.