Unit converters
546 unit converters: length, weight, temperature, volume, speed, pressure, energy, data and cooking measures. Type a value, pick the units and get an exact result with the conversion factor shown, free in your browser.
Sieve mesh size converter
Read any sieve callout as a real opening and back: 100 US mesh is a 150 µm opening, or 0.15 mm, so lab sieve stacks, supplier sheets and particle-size specs…
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Solar mass, radius & luminosity converter
One solar mass is 1.98847 × 10³⁰ kg. This converter turns M☉, R☉ and L☉ into kilograms, metres and watts, or into Earth and Jupiter units, for star tables…
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Sound absorption converter
100 sabins are 9.290304 metric sabins. Convert an absorption area between sabins, metric sabins and square metres, feet, centimetres or yards when a room…
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Sound power converter
1 watt of acoustic power is exactly 120 dB re 1 pW. Convert sound power between watts, picowatts through megawatts, BTU per hour, erg per second and the level…
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Specific impulse converter
450 seconds of Isp is 4412.9925 m/s of exhaust velocity. Convert specific impulse between seconds, m/s, N·s/kg, km/s, ft/s and lbf·s/lb with standard gravity of…
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Square km to square miles
2.589988110336 square kilometres are exactly 1 square mile, because the mile has been fixed at 1.609344 km since 1959.
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Spring stiffness converter
1000 N/m is 5.710147154733 lbf/in. Convert a spring rate between N/m, N/mm, kN/m, lbf/in, lbf/ft and kg/mm or kgf/mm when a coil-spring catalogue, a suspension…
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Guitar string gauge converter
A 9-gauge high E is 9 thousandths of an inch: 0.009 in, or 0.2286 mm. Turn the gauge printed on a string packet into mils, inches, millimetres, centimetres and…
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Surface charge density converter
1 C/m² is 0.0001 C/cm². Convert surface charge density between coulombs per square metre, centimetre, millimetre, inch and foot, plus milli-, micro- and…
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Thermal conductance converter
1 W/K is 1.895634240627 BTU/(h·°F). Convert a heat flow per degree of temperature difference between SI, calorie and BTU units, and get the factor applied plus…
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Thermal expansion coefficient converter
0.000012 per kelvin is 12 ppm/K. Switch a linear expansion coefficient α between kelvin, Celsius, Fahrenheit and Rankine forms, as plain reciprocal degrees…
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Thread count converter
200 TPI is 78.740157480315 threads per centimetre. Convert a fabric's thread density between TPI, threads per centimetre, per ten centimetres, per metre and per…
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Thread pitch converter
A 20 TPI bolt has a 1.27 mm pitch. Switch a screw thread between threads per inch and metric pitch, and see inch pitch, threads per centimetre and per…
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Torr to PSI converter
760 torr, one standard atmosphere, is 14.695948775513 psi. Turn a vacuum or lab reading in torr into the pounds per square inch shown on US gauges and…
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Turbidity converter
10 NTU is 10 FNU on formazin standards. Convert a water-clarity or haze reading between NTU, FNU, FTU, FAU, JTU, brewery EBC and silica ppm, and get the factor…
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Vacuum pressure converter
760 torr make one standard atmosphere, 101,325 Pa. Convert vacuum readings between torr, millitorr, microns, mmHg, millibar, pascals, kilopascals, hectopascals…
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Water conductivity & TDS converter
Turn a meter reading into the unit your log asks for: 500 µS/cm becomes 250 ppm of dissolved solids with the usual 0.5 factor, which you can change to match…
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Base62 number converter
1000 in base 62 is G8: this converter turns whole numbers into short, link-friendly codes built from digits, capital letters and small letters, and decodes them…
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Binary to hex converter
1010 in binary is A in hexadecimal: each group of four bits becomes one hex digit, so long runs of zeros and ones turn into short, readable values for masks…
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Chinese number converter
1234 becomes 一千二百三十四 in everyday Chinese numerals: convert whole numbers into common or anti-fraud financial characters for receipts, invoices and lessons, or…
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Number to currency words
1250.50 becomes one thousand two hundred fifty and 50/100, the wording banks expect on the written line of a cheque: enter the amount and copy the phrase.
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Decimal to binary converter
42 in binary is 101010, six bits long: enter any whole number and get its binary digits for homework, bit masks or permission flags. Free in your browser.
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Decimal to fraction converter
0.75 is 3/4 and 0.(3) is exactly 1/3: enter a finite or repeating decimal and get the fraction already reduced to lowest terms, ready for homework or a recipe.
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Decimal to octal converter
64 in decimal is 100 in octal, because eight times eight is sixty-four: enter a whole number and get its base-8 digits, with negative numbers keeping their…
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Decimal to percent converter
0.25 becomes 25%: the converter multiplies any decimal by 100, so a rate stored as 0.073 reads as 7.3% on a label or a report, and negatives keep their sign.
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Duodecimal converter
144 in decimal is 100 in base 12, because it is exactly twelve dozens: convert whole numbers to dozenal digits, with X for ten and E for eleven, or decode them…
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Fraction to decimal converter
3/8 is 0.375 and 6/8 is 0.75, shown reduced as 3/4: enter the top and bottom numbers and get the decimal, with a clear warning instead of nonsense if the bottom…
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Gray code converter
Binary 1011 becomes Gray 1110 here, and Gray converts back to binary just as exactly, with leading zeros kept so a fixed-width answer stays fixed.
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Hex to binary converter
0xFF in binary is 11111111: each hex digit maps to four bits, so F becomes 1111. Paste a value with or without the 0x prefix and get both the short binary and…
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Hex to decimal converter
0xFF is 255 in decimal: fifteen times sixteen plus fifteen. Paste any hex value, with or without 0x and in either case, and see the decimal result together with…
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Float to IEEE-754 converter
3.14 in double precision is stored as 0x40091EB851EB851F: one sign bit, eleven exponent bits and 52 significand bits, each shown separately.
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Spell a number in English
1234 becomes one thousand two hundred thirty-four, in American English with hyphenated tens and no and after hundred.
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Spell a number in Spanish
1234 in Spanish is mil doscientos treinta y cuatro, written the formal way you would put on a cheque or a contract.
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Percent to decimal converter
25% is 0.25 as a decimal: a percent means parts per hundred, so you simply divide by 100. Paste values with or without the % sign, including 12.5, values above…
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Large Roman numerals converter
4000 becomes I̅V̅ in Roman numerals: the bar over the letters multiplies them by a thousand, while 2024 stays plain MMXXIV.
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Number rounding tool
3.14159 rounded to two decimal places is 3.14, and an exact half always moves away from zero, so 2.5 becomes 3 and -2.5 becomes -3.
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Scientific notation converter
1234.5 in scientific notation is 1.2345e3: a mantissa between 1 and 10 times ten to the third. Expand e-notation back to plain digits just as easily, for lab…
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Ordinal words converter
21 becomes twenty-first, with 21st alongside when space is tight. Only the last word turns into a rank, so one hundred one reads one hundred first, never oneth…
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Thai numeral converter
2026 in Thai numerals is ๒๐๒๖: each digit is swapped for its Thai shape and the value stays the same.
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Add thousands separators
1234567.89 becomes 1,234,567.89 in US style with two decimals, while European style writes 1,234,000 as 1.234.000.
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Two's complement converter
-5 in 8 bits is 11111011, the exact pattern a register holds, and 11111011 decodes back to -5. Values that do not fit the width, such as 128 in 8 bits, are…
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Miles to km converter
10 miles are exactly 16.09344 km, because one international mile is 1.609344 km to the last digit.
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Feet to cm converter
Turn feet into centimeters with the exact factor: 1 ft is 30.48 cm, the definition used in science, construction and schools since 1959.
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Absolute humidity converter
10 g/m³ of water vapor is 4.36995724033 grains/ft³: the converter moves absolute humidity between six metric and imperial units through kg/m³, with exact…
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Absorbance transmittance converter
An absorbance of 1 means 10 %T: the converter moves readings between A, OD, T, %T and mAU through the rule that absorbance is minus the base-ten log of…
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Acoustic impedance converter
1.5 MRayl, the figure often quoted for soft tissue, is 1,500,000 rayls. The converter moves acoustic impedance between seven units, from cgs rayls to Pa·s/m…
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Acres to square feet converter
One acre is exactly 43,560 square feet, and this converter applies that single multiplication to any acreage, so a lot size from a deed or a farm report lands…
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Bar to kPa converter
1 bar is exactly 100 kPa, so 2.5 bar on a European gauge reads 250 kPa on an SI datasheet. This converter applies that exact factor to compressor charts…
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Bar to PSI converter
One bar, exactly 100,000 pascals, is 14.503773773021 psi. This converter applies that full factor instead of a rounded 14.5, so European tyre placards, boiler…
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Barrels to liters converter
One oil barrel is exactly 158.987294928 liters, 42 US gallons by definition. This converter applies that factor to crude and product volumes, so cargo tickets…
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BTU per hour to watts converter
One BTU per hour is 0.293071070172 watts, taken from the exact International Table definition instead of a rounded shortcut.
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BTU to joules converter
One BTU is exactly 1055.05585262 joules under the International Table definition, so a heating load or gas ticket in BTU becomes the joule figure a lab report…
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CC to cubic inches converter
16.387064 cc is exactly one cubic inch, because the inch is defined as 2.54 cm. Convert engine displacement, mould cavities or packaging volumes from cc to…
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CFM to cubic meters per hour converter
100 CFM is exactly 169.901079552 m³/h. Turn the airflow on a US fan, nameplate or HVAC schedule into the cubic metres per hour used in European and ISO…
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CM to feet converter
152.4 cm is exactly 5 feet, because one foot is defined as 30.48 cm. Convert heights, room sizes or furniture dimensions from centimetres to feet with that…
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Cooling capacity converter
One ton of refrigeration is exactly 12,000 BTU/h, or 3.516852842067 kW: convert chiller and heat-pump capacity between tons, kilowatts, BTU per hour, watts and…
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Cubic feet to gallons converter
One cubic foot is about 7.480519480519 US gallons: convert a tank, aquarium, pool or rain barrel measured in cubic feet into US liquid gallons, with the exact…
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Cubic inches to cc converter
2 cubic inches are exactly 32.774128 cc: convert engine displacement badges, syringe notes, small-parts packaging and textbook problems from cubic inches to…
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Cups to ml converter
1 US cup is exactly 236.5882365 ml: turn recipe-card cups into the millilitres printed on nutrition labels, measuring jugs, lab glassware and international…
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Current density converter
1 A/mm² is 1,000,000 A/m²: convert current density between nine units, from A/m², A/cm² and A/mm² to A/in², A/ft² and their milli or kilo variants, for cable…
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