Scientific measurement requires precision and standardization across disciplines: SI units provide a universal measurement language Derived units combine base units for complex quantities Conversion accuracy is critical for reproducible results 7 SI base units: Meter (m) -- length Kilogram (kg) -- mass Second (s) -- time Ampere (A) -- electric current Kelvin (K) -- temperature Mole (mol) -- amount of substance Candela (cd) -- luminous intensity Defined by the 2019 SI redefinition fixing fundamental constants. Precision: consistency of repeated measurements Accuracy: closeness to the true value Arithmetic uses IEEE 754 binary64; displayed values are rounded Significant figures should match your measurement precision Always verify critical values against standards Professional-grade conversion tools built for scientists, engineers, and students. From electromagnetic quantities to thermodynamic properties, calculators use published SI and customary factors. Arithmetic runs in IEEE 754 binary64; displayed results are rounded for readability. How factors are sourced, how the library is updated, and how IEEE 754 rounding is treated are documented on the About page . High-value science converters Jump from the science hub into published pair calculators for pressure, power, force, and everyday lab units. PSI to kilopascals kilopascals to PSI atmospheres to PSI kilopascals to bar horsepower to kilowatts kilowatts to horsepower watts to horsepower kilowatts to Pferdestärke watts to kilowatts newtons to kilogram-force kilogram-force to newtons kilowatt-hours to gigajoules millimeters to inches mils to millimeters feet to centimeters miles per hour to kilometers per hour Celsius to Fahrenheit degrees to radians Specialty Science Calculators Advanced calculation tools for engineering and scientific analysis. Beam Deflection Calculator Calculate beam deflection for simply supported, cantilever, and fixed beams under various loading conditions. Circuit Analysis Calculator Analyze electrical circuits using Ohm's law. Calculate voltage, current, resistance, and power. Thermodynamic Properties Calculate thermodynamic properties like density, specific heat, and thermal conductivity for common substances. Aviation Converters Pilot tools for fuel weight, Mach/TAS, CAS/TAS, altimeter settings, flight levels, NM distance, crosswind, and RVR. Aviation Fuel Weight Convert Jet A, AVGAS, and Jet B fuel liters or gallons to pounds and kilograms for weight-and-balance planning. Convert Mach number to true airspeed using outside air temperature or ISA altitude. Shipping Converters Freight tools for TEU/FEU, chargeable weight, container load planning, revenue tons, voyage time, and bunker fuel. Container TEU / FEU Convert 20′, 40′, 40′ HC, and 45′ containers to TEU/FEU with typical internal CBM and payload. Physics & Mechanics Newtons, pound-force, dynes, and more

Pascal, bar, PSI, atmosphere mph, km/h, m/s, knots Joules, calories, kWh, BTU Watts, horsepower, BTU/h Acceleration, density, torque Electromagnetism & Waves Voltage, current, resistance, capacitance Tesla, gauss, weber, henry Lumens, lux, candela, illuminance Gray, sievert, becquerel, rem Sound & Acoustics Decibels, sound pressure, intensity Thermal & Fluid Sciences Heat & Thermodynamics Thermal conductivity, heat capacity, heat flux Flow rate, viscosity, surface tension Celsius, Fahrenheit, Kelvin Scientific Constants Reference Fundamental physical constants used in scientific calculations. Why Precise Unit Conversion Matters in Science In 1999, NASA's Mars Climate Orbiter was lost because one engineering team used imperial units (pound-force seconds) while another used metric units (newton-seconds). This $327.6 million mission failure demonstrates why precise unit conversion is not just academic -- it's critical for real-world outcomes. In medicine, dosing errors from unit confusion can be life-threatening. A prescription written in milligrams administered as micrograms delivers 1000x the intended dose. Pharmaceutical standards require precise unit notation and conversion. In physics research, the precision of unit conversion directly affects experimental reproducibility. The 2019 SI redefinition fixed fundamental constants to exact values, establishing a measurement framework that enables scientific collaboration across the globe. Common questions about our science and engineering conversion tools. We offer specialized converters for radiation (gray, sievert, becquerel), electricity (voltage, current, resistance, capacitance), magnetism (tesla, gauss, weber), sound (decibels, sound pressure), light (lumens, lux, candela), heat (thermal conductivity, heat capacity), fluid dynamics (flow rate, viscosity), force, pressure, energy, power, and engineering units. Calculations use IEEE 754 binary64, which has about 15–17 decimal digits of significand. Displayed results are usually rounded. Factors follow published SI and customary definitions (NIST, BIPM, and domain standards). For critical work, verify against the primary standard. See the About page for sources and limits. Absolutely. Our converters and calculators are designed for educational use as well as professional work. The beam deflection calculator, circuit analysis tool, and thermodynamic property calculator are commonly used by engineering students for homework, lab work, and exam preparation. The Thermodynamic Property Calculator computes properties like density, specific heat capacity, viscosity, and thermal conductivity for common gases and liquids at specified temperatures and pressures. It supports multiple substances and is useful for heat transfer and thermodynamic process calculations. Radiation units measure different aspects: absorbed dose (gray, rad), equivalent dose (sievert, rem), activity (becquerel, curie), and exposure (roentgen). Converting between them requires understanding the radiation type and weighting factors. Our converter handles these relationships accurately for all radiation measurement types. High-value science converters Jump from the science hub into published pair calculators for pressure, power, force, and everyday lab units. Popular pair converters PSI to kilopascals kilopascals to PSI atmospheres to PSI kilopascals to bar horsepower to kilowatts kilowatts to horsepower watts to horsepower kilowatts to Pferdestärke watts to kilowatts newtons to kilogram-force kilogram-force to newtons kilowatt-hours to gigajoules millimeters to inches mils to millimeters feet to centimeters miles per hour to kilometers per hour Celsius to Fahrenheit degrees to radians engineering conversion pressure conversion power conversion Learn and reference science and engineering guides conversion tutorials conversion formulas conversion charts sources and precision