Unit Converters
Universal Unit Converter
Any unit → any unit
Convert across all physical-quantity categories (length, mass, volume, energy, power, etc.).
Convert →Length Unit Converter
m · km · mi · ft · in
Convert between meters, kilometers, miles, feet, inches, and other length units.
Convert →Mass Unit Converter
kg · g · lb · oz · tonne
Convert between kilograms, grams, pounds, ounces, and other mass units.
Convert →Volume Unit Converter
L · mL · gal · m³ · ft³
Convert between liters, milliliters, gallons, cubic meters, and other volume units.
Convert →Area Unit Converter
m² · ft² · acre · hectare
Convert between square meters, square feet, acres, hectares, and other area units.
Convert →Speed Unit Converter
m/s · km/h · mph · knots
Convert between meters per second, kilometers per hour, miles per hour, knots, etc.
Convert →Pressure Unit Converter
Pa · psi · bar · atm · mmHg
Convert between pascals, psi, bar, atmospheres, mmHg, and other pressure units.
Convert →Force Unit Converter
N · lbf · kgf · dyne
Convert between newtons, pound-force, kilogram-force, dynes, and other force units.
Convert →Energy Unit Converter
J · cal · kWh · BTU · eV
Convert between joules, calories, kilowatt-hours, BTUs, and other energy units.
Convert →Power Unit Converter
W · hp · kW · BTU/h
Convert between watts, horsepower, kilowatts, BTU per hour, and other power units.
Convert →Density Converter
kg/m³ · g/cm³ · lb/ft³
Convert between kilograms per cubic meter, grams per cubic centimeter, pounds per cubic foot.
Convert →Acceleration Converter
m/s² · ft/s² · g · gal
Convert between meters per second squared, feet per second squared, g, gal, and others.
Convert →Time Converter
s · min · h · day · year
Convert between seconds, minutes, hours, days, weeks, months, and years.
Convert →Angle Converter
rad · deg · grad · turn
Convert between radians, degrees, gradians, and turns.
Convert →Frequency Converter
Hz · kHz · MHz · rpm
Convert between hertz, kilohertz, megahertz, rpm, and other frequency units.
Convert →Torque Converter
N·m · ft·lb · in·lb · kgf·m
Convert between newton-meters, foot-pounds, inch-pounds, and kilogram-force meters.
Convert →Voltage Converter
V · mV · kV · μV
Convert between volts, millivolts, kilovolts, microvolts, and other voltage units.
Convert →Current Converter
A · mA · μA · kA
Convert between amperes, milliamperes, microamperes, and kiloamperes.
Convert →Resistance Converter
Ω · kΩ · MΩ · mΩ
Convert between ohms, kilohms, megohms, and milliohms.
Convert →Viscosity Converter
Pa·s · cP · poise · lb/(ft·s)
Convert between dynamic viscosity units — pascal-seconds, centipoise, poise, and others.
Convert →Single-purpose unit converters for length, mass, volume, area, speed, pressure, force, energy, power, density, acceleration, time, angle, frequency, torque, voltage, current, resistance, and viscosity.
When to use these calculators
Quick-reference unit conversion tools. Each converter handles the standard set of units in its domain and shows the conversion factor used.
Frequently Asked Questions
- How does the calculator show its work?
- Each calculator displays the substituted arithmetic step-by-step below the solution, so the user can verify the math by hand if needed. The 'Copy result' button captures the full formula → substitution → answer block.
- Are the formulas cross-verified?
- Every calculator's math has been cross-verified against textbook references and round-trip consistency tests (solve A from B, then solve B from A — the result must match the input). Spot-checks against Wolfram Alpha confirm the precision.
- How do I switch between solving for different variables?
- Most calculators in this category support multiple solve-for modes. Pick the unknown variable from the pill-toggle (or equation-card group) above the input fields, then enter the known values. The calculator auto-computes as you type.