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MeasureMate

Unit Converters

Each converter here uses the exact legal definition of its units (a mile is 1,609.344 m, a pound is 0.45359237 kg, a US gallon is 3.785411784 L), so results match engineering tables rather than rounded rules of thumb.

Every page also explains where the unit came from and the mix-ups people actually make, such as decimal gigabytes versus binary gibibytes, or the three different horsepowers still in use.

16 tools · updated

Temperature Converter Convert a temperature between Celsius, Fahrenheit and Kelvin, with a note on how it feels and a check against absolute zero. Length Converter Convert a distance between millimeters, centimeters, meters, kilometers, inches, feet, yards and miles using exact definitions. Weight Converter Convert mass between kilograms, grams, milligrams, pounds, ounces, stone and metric tonnes, with a stone-and-pounds reading. Volume Converter Convert liquid volumes between liters, milliliters, US gallons, quarts, pints, cups, fluid ounces, spoons and the imperial gallon. Speed Converter Convert speeds between km/h, mph, m/s, ft/s and knots, with the matching running or cycling pace per kilometer and per mile. Area Converter Convert an area between square meters, square centimeters, square kilometers, square inches, square feet, square yards, square miles, acres and hectares. Pressure Converter Convert pressure between pascals, hPa, kPa, MPa, bar, psi, atmospheres, torr, mmHg and inches of mercury. Energy Converter Convert energy between joules, kJ, MJ, calories, kilocalories, watt-hours, kWh, BTU, electronvolts and foot-pounds. Power Converter Convert power between watts, kilowatts, megawatts, mechanical, metric and electrical horsepower, BTU per hour and tons of refrigeration. Data Size Converter Convert digital storage between bits and bytes, decimal units (kB, MB, GB, TB) and binary units (KiB, MiB, GiB, TiB). Angle Converter Convert angles between degrees, radians, gradians, arcminutes, arcseconds, milliradians, NATO mils and turns. Force Converter Convert force between newtons, kilonewtons, pounds-force, kips, kilogram-force, ounces-force, poundals and dynes using exact factors. Frequency Converter Convert frequency between hertz, kHz, MHz, GHz, rpm, beats per minute and radians per second, with the period of one cycle. Torque Converter Convert torque between newton-meters, pound-force feet and inches, ounce-force inches, kilogram-force meters and centimeters, and decanewton-meters. Density Converter Convert density between kg/m³, g/cm³, g/mL, kg/L, g/L, lb/ft³, lb/in³, oz/in³ and pounds per US gallon. Acceleration Converter Convert acceleration between m/s², ft/s², in/s², standard gravity (g), gals, km/h per second and mph per second.

Picking the right converter

Kilograms or newtons?

A kilogram is mass; a newton is force. Bathroom scales, recipes and luggage limits all use mass, so the weight converter is the right tool. Engineering loads, thrust and spring ratings are forces, which belong in the force converter. The bridge between them is standard gravity, fixed by definition at 9.80665 m/s², which is also the “g” in the acceleration converter.

Kilowatt-hours or kilowatts?

Energy is an amount and power is a rate. Your electricity bill counts kilowatt-hours, a food label counts kilocalories and a gas furnace is sized in BTU; convert those with the energy converter. Motor ratings, solar panels and car engines are quoted in watts or horsepower, which the power converter handles. Multiply power by running time to get energy: a 2 kW heater left on for three hours uses 6 kWh.

Why does torque share a unit with energy?

Both reduce to newtons times meters, but torque is a twisting effort about an axis while energy is work done along a path. Wrench settings and engine torque curves go in the torque converter, which keeps them in N·m, lbf·ft and lbf·in so the two never get mixed up.

Which gallon?

A US gallon is 3.785411784 liters and an imperial gallon is 4.54609 liters, about 20% larger. The volume converter lists both. If the real question is how many grams are in a cup of an ingredient, you need its density as well, which is what the cooking conversion tool and the density converter are for.

Why does a 1 TB drive show about 931 GB?

Drive makers count in decimal terabytes (10¹² bytes), while many operating systems divide by powers of 1024 and still print “GB”. The data size converter keeps the decimal units (kB, MB, GB) separate from the binary ones (KiB, MiB, GiB) so you can see that 10¹² bytes is 931.3 GiB.

Rates of turning and readings on a gauge

One hertz is one cycle per second, so 50 Hz is 3,000 RPM; the frequency converter also gives radians per second. Tire gauges read psi or bar and blood-pressure cuffs read millimeters of mercury, all of which the pressure converter covers. Survey and map angles in degrees, radians, gradians or mils go through the angle converter.