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Convert between 48 weight & mass units instantly. Convert between kilograms, pounds, ounces, grams, stones, and metric tons.
A unit converter translates a measurement expressed in one unit into its equivalent in another unit. Converting between metric and imperial, or between two metric prefixes, requires applying a conversion factor - a fixed multiplier that relates the two scales.
For linear unit pairs (like metres and feet), the formula is always:
output = input × factor
For non-linear pairs (temperature scales like Celsius and Kelvin, or Fahrenheit and Celsius), the relationship includes an additive offset:
°F = (°C × 9/5) + 32
K = °C + 273.15
This tool handles both types automatically.
| Category | What it measures | Common example |
|---|---|---|
| Length | Distance, size | metres, feet, miles |
| Mass | Amount of matter | kilograms, pounds, ounces |
| Volume | Space occupied by a liquid or gas | litres, gallons, fluid ounces |
| Temperature | Thermal energy | Celsius, Fahrenheit, Kelvin |
| Speed | Rate of movement | km/h, mph, knots, m/s |
| Area | Two-dimensional extent | square metres, acres, hectares |
| Time | Duration | seconds, minutes, hours, days |
| Category | What it measures |
|---|---|
| Energy | Work done, heat, electrical energy (joules, BTU, kWh, cal) |
| Power | Rate of energy transfer (watts, horsepower, BTU/hr) |
| Pressure | Force per unit area (Pa, psi, bar, atm, mmHg) |
| Force | Push or pull on an object (newtons, pound-force, kgf) |
| Torque | Rotational force (N·m, ft·lb, in·lb, kgf·cm) |
| Frequency | Cycles per second (Hz, kHz, MHz, GHz, rpm) |
| Angle | Rotation from a reference direction (degrees, radians, gradians) |
| Density | Mass per volume (kg/m³, g/cm³, lb/ft³) |
| Category | What it measures |
|---|---|
| Digital Storage | File and drive sizes (bits, bytes, KB, MB, GB, TB, PB) |
| Data Transfer Rate | Network throughput (bps, Kbps, Mbps, Gbps) |
| Category | What it measures |
|---|---|
| Electric Current | Flow of charge (amperes, milliamperes) |
| Electric Charge | Total charge (coulombs, milliampere-hours) |
| Voltage | Electrical potential difference (volts, millivolts, kilovolts) |
| Capacitance | Ability to store charge (farads, microfarads, picofarads) |
| Resistance | Opposition to current (ohms, kilohms, megaohms) |
| Inductance | Opposition to change in current (henries, millihenries) |
| Category | What it measures |
|---|---|
| Fuel Economy | Distance per volume of fuel (mpg, L/100 km, km/L) |
| Specific Heat | Energy per mass per degree (J/kg·K, BTU/lb·°F) |
| Dynamic Viscosity | Resistance to flow (Pa·s, poise, centipoise) |
| Kinematic Viscosity | Viscosity normalised for density (m²/s, stokes) |
| Illuminance | Light intensity at a surface (lux, foot-candle) |
The metric system uses a base-10 structure with SI prefixes:
| Prefix | Symbol | Multiplier |
|---|---|---|
| tera | T | 10¹² |
| giga | G | 10⁹ |
| mega | M | 10⁶ |
| kilo | k | 10³ |
| (base) | 1 | |
| milli | m | 10⁻³ |
| micro | μ | 10⁻⁶ |
| nano | n | 10⁻⁹ |
| pico | p | 10⁻¹² |
The imperial system is not base-10. Conversion factors are often non-obvious:
This is why a converter is useful - there is no pattern to memorise.
Every unit in this converter is defined by its relationship to an SI base unit. The conversion factor between any two units in the same category is:
factor(A → B) = factor(A → SI) / factor(B → SI)
For example, to convert miles to kilometres:
All conversions in this tool are computed from authoritative NIST definitions.
All conversion factors are stored as IEEE 754 double-precision floating-point numbers (64-bit). This gives roughly 15–17 significant decimal digits of accuracy - more than sufficient for any practical application.
Results are displayed with up to 7 significant figures and switch to scientific notation for values larger than 10¹² or smaller than 10⁻⁶.
This utility is provided for general informational and calculation purposes. Always verify critical computation outputs prior to professional deployment or financial use. Computations execute client-side in your browser wherever supported to uphold user data privacy. See our Terms of Service and Privacy Policy for full governance details.
Quick reference: common weight & mass conversions for values 1-100.
| Value | kg | g | lb | oz | t | st |
|---|---|---|---|---|---|---|
| 1 kg | 1 | 1.00e+3 | 2.2046 | 35.274 | 0.001 | 0.157473 |
| 5 kg | 5 | 5.00e+3 | 11.023 | 176 | 0.005 | 0.7873652 |
| 10 kg | 10 | 1.00e+4 | 22.046 | 353 | 0.01 | 1.5747 |
| 25 kg | 25 | 2.50e+4 | 55.116 | 882 | 0.025 | 3.9368 |
| 50 kg | 50 | 5.00e+4 | 11 | 1.76e+3 | 0.05 | 7.8737 |
| 100 kg | 100 | 1.00e+5 | 22 | 3.53e+3 | 0.1 | 15.747 |