Physics Unit Conversion Table
| Unit | Symbol | SI Equivalent | Category |
|---|---|---|---|
| Foot-pound | ft·lbf | 1.35582 Nm | Torque |
| Horsepower | hp | 745.7 W | Power |
| BTU | BTU | 1,055.06 J | Energy |
| PSI | psi | 6,894.76 Pa | Pressure |
| Pound-force | lbf | 4.44822 N | Force |
| Mile/hour | mph | 1.60934 km/h | Speed |
| Gallon (US) | gal | 3.78541 L | Volume |
| Calorie | cal | 4.184 J | Energy |
Mechanical Unit Conversion Standards
Force & Torque Units
Force units: Newton (N), pound-force (lbf), kilogram-force (kgf), dyne (dyn). Key conversions: 1 N = 0.2248 lbf = 0.1020 kgf = 100,000 dyn. Torque units: Newton-meter (Nm), foot-pound (ft-lbs), inch-pound (in-lbs). 1 Nm = 0.7376 ft-lbs = 8.851 in-lbs. For dedicated torque tools, see our torque converter.
Energy & Work Units
The joule (J) is the SI unit of energy: 1 J = 1 N·m = 1 W·s. Other energy units: calorie (cal) = 4.184 J, BTU = 1,055.06 J, kilowatt-hour (kWh) = 3,600,000 J, electron-volt (eV) = 1.602×10⁻¹⁹ J. Energy and work are dimensionally identical: both measure force × distance.
Power Unit Conversion
Power is the rate of energy transfer. The watt (W) is the SI unit: 1 W = 1 J/s. 1 horsepower (hp) = 745.7 W. 1 BTU/hour = 0.2931 W. For electrical power conversions involving watts, volts, and amps, use our power conversion tools.
Electrical Unit Conversion in Physics
Voltage, Current & Resistance Units
Voltage (V), current (A), and resistance (Ω) are related by Ohm's Law: V = I × R. The volt is defined as the potential difference that moves one coulomb of charge with one joule of energy. Common scales: millivolts (mV) for sensors, volts (V) for electronics, kilovolts (kV) for power transmission.
Ohm's Law Applications
Ohm's Law (V = IR) enables conversion between electrical units: Power = V × I = I²R = V²/R. These relationships are fundamental to circuit design, power system engineering, and electrical safety calculations. For practical power calculations, visit our watt to voltage converter.