Science & Engineering Calculators
Solve real-world science and engineering problems with our free calculators. Convert pressure and energy units, size electrical wire, calculate BTU requirements, and check wind chill or temperature conversions. Built for students, engineers, technicians, and DIY enthusiasts.
Unit Conversions
Convert between pressure, energy, speed, and temperature units.
Pressure Converter
Convert between PSI, bar, Pascal, kPa, atm, mmHg, and torr.
Energy Converter
Convert between joules, calories, kWh, BTU, and electron volts.
Speed Converter
Convert between mph, km/h, m/s, knots, and Mach number.
Temperature Converter
Convert between Celsius, Fahrenheit, Kelvin, and Rankine.
Scientific Notation Calculator
Convert numbers to and from scientific notation and perform operations.
Electrical Engineering
Wire sizing, load calculation, and power tools.
Wire Size Calculator
Determine the correct AWG wire gauge for your electrical project.
Electrical Load Calculator
Calculate total electrical load for circuits and panel sizing.
Horsepower Calculator
Calculate horsepower from torque, RPM, or electrical inputs.
HVAC & Weather
BTU sizing and wind chill estimation.
Frequently Asked Questions
How do I convert between pressure units?
The pressure converter handles PSI, bar, Pascal, kPa, atm, mmHg, and torr. Enter a value in any unit and instantly see the equivalent in all others. This is essential for HVAC, hydraulics, weather data, and tire pressure when working across metric and imperial systems.
What wire size do I need for my electrical project?
The wire size calculator determines the correct AWG (American Wire Gauge) based on current draw in amps, wire length, and acceptable voltage drop. For most residential circuits, 14 AWG handles 15 amps and 12 AWG handles 20 amps. Longer runs or higher loads require thicker wire to prevent overheating and voltage loss.
How do I calculate BTU for heating or cooling?
The BTU calculator estimates the heating or cooling capacity needed for a room based on square footage, ceiling height, insulation quality, sun exposure, and climate zone. A rough rule is 20 BTU per square foot for cooling, but our calculator refines this with your specific conditions. Proper BTU sizing prevents wasted energy and uncomfortable temperatures.
How does wind chill work?
Wind chill measures how cold it feels on exposed skin when wind is factored in. The wind chill calculator uses the NWS formula combining air temperature and wind speed. For example, 30°F with a 15 mph wind feels like 19°F. Wind chill becomes dangerous below -20°F, where frostbite can occur in minutes.