Unit Converters for Science & Engineering
Find the Units to Convert
Common Conversions
- centimeters to inches
- kilograms to pounds
- Celsius to Fahrenheit
- millimeters to inches
- meters to feet
- kilometers to miles
- centimeters to feet
- grams to ounces
- inches to feet
- Celsius to Kelvin
- meters to yards
- pounds to ounces
- kilowatts to horsepower
- kilocalories to kilojoules
- N·m to pound-feet
- kWh to BTU
- psi to bar
- kilopascals to psi
- pascals to inH₂O
- pascals to psi
- mmHg to kilopascals
- atmospheres to psi
- inHg to millibars
- millibars to pascals
- torr to pascals
- megapascals to psi
- CFM to m³/h
- CFM to L/s
- GPM to L/min
- sccm to SLPM
- L/min to m³/h
- cfm/ft² to L/m²/s
- m/s to ft/min
- m² to square feet
- cm² to in²
- liters to US gallons
- cubic meters to cubic feet
- hours to minutes
- inches to centimeters
- pounds to kilograms
- Fahrenheit to Celsius
- inches to millimeters
- feet to meters
- miles to kilometers
- feet to centimeters
- ounces to grams
- feet to inches
- Kelvin to Celsius
- yards to meters
- ounces to pounds
- horsepower to kilowatts
- kilojoules to kilocalories
- pound-feet to N·m
- BTU to kWh
- bar to psi
- psi to kilopascals
- inH₂O to pascals
- psi to pascals
- kilopascals to mmHg
- psi to atmospheres
- millibars to inHg
- pascals to millibars
- pascals to torr
- psi to megapascals
- m³/h to CFM
- L/s to CFM
- L/min to GPM
- SLPM to sccm
- m³/h to L/min
- L/m²/s to cfm/ft²
- ft/min to m/s
- square feet to m²
- in² to cm²
- US gallons to liters
- cubic feet to cubic meters
- minutes to hours
Unit Converters — Full Versions
Common Converters
Engineering Converters
Fluids Converters
Filtration & Permeability Converters
Engineering Calculators & Tools
- Face Velocity Calculator – Airflow + filter, duct or hood size → face velocity (fpm, m/s), or solve for flow or area.
- Air Permeability Calculator – Tester flow + test area (ISO 9237, ASTM D737 presets) → permeability in mm/s, L/m²/s, cfm/ft².
- SCFM to ACFM Calculator – Standard ↔ actual gas flow (SCFM/ACFM, Nm³/h) at any temperature, pressure or altitude.
- Reynolds Number Calculator – Velocity, diameter, density and viscosity in any units → Re and flow regime.
- Pipe Pressure Drop Calculator – Flow + pipe size + material + fluid → pressure drop, velocity, Re and friction factor.
- Ideal Gas Law Calculator – Solve PV = nRT for P, V, n or T in any pressure, volume and temperature units.
- Bubble Point Pore Size Calculator – Bubble-point pressure + wetting liquid → largest pore size (Young–Laplace), or the reverse.
- Ohm's Law Calculator – Any two of volts, amps, ohms and watts → the other two.
- Bulk Unit Converter – Paste a column or table from Excel, convert every value, copy back or download CSV.
Guides
About Units and the SI
Scientific Converters converts pressure, flow rate, air permeability, area, volume and time with exact factors. For example, 1 psi = 6894.757293 Pa and 1 CFM/ft² = 5.08 L/(m²·s).
The International System of Units (SI) is built on seven base units, among them the metre, kilogram and second. Since 2019 each is defined by a fixed constant of nature, such as the speed of light or the Planck constant. Units like the pascal (N/m²) and the cubic metre per second are derived from these base units. Many customary units are exact multiples of SI units: the inch is exactly 25.4 mm and the pound exactly 0.45359237 kg, so a psi is exactly 6894.757293168… Pa. Others, such as inches of water, depend on a reference density and temperature, which every page here states. Scientific Converters stores each factor exactly, cites NIST SP 811 or the BIPM SI Brochure, and calculates with 50-digit decimal arithmetic before rounding the display.