Changelog
– New categories, calculators, guides and data API
- Ten new categories: length, temperature (with exact offset handling for °C, °F, K, °R), weight and mass, energy, power, force, torque, density, dynamic viscosity and kinematic viscosity.
- New formula calculators: Reynolds number, pipe pressure drop (Darcy–Weisbach, Colebrook), ideal gas law, bubble point to pore size and Ohm's law.
- Six in-depth guides, printable conversion charts for every category, an embeddable converter widget and a free JSON data API (CC BY 4.0).
– Engineering calculators and bulk conversion
- New face velocity calculator: solve for velocity, airflow or face area from W × H, round or area inputs.
- New air permeability calculator with ISO 9237 and ASTM D737 test-head presets and a copyable report line.
- New SCFM to ACFM calculator with six standard references, gauge or absolute pressure and altitude.
- New bulk unit converter for pasted lists and spreadsheet tables, including units written in cells.
– Launch (data version 2026-10-15)
- 16 categories: Length, Temperature, Weight and Mass, Energy, Power, Force, Torque, Density, Dynamic Viscosity, Kinematic Viscosity, Pressure, Flow Rate, Face Velocity & Air Permeability, Area, Volume, Time.
- 145 units, 1348 conversion pages, of which 322 have field-specific content.
- Water and mercury column units use the conventional definitions (ρ = 1000 kg/m³ and 13 595.1 kg/m³, standard gravity) and state them on every page. The inch of water at 60 °F (248.84 Pa, NIST) is a separate unit.
- Standard flow units (sccm, SLPM) are separated from actual flow units (cm³/min, L/min), with selectable reference conditions.
- Inch of mercury stored as the exact conventional value 3386.388640341 Pa.
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