Temperature
Convert between Celsius, Fahrenheit, Kelvin, and Rankine temperature scales.
Celsius (°C) Fahrenheit (°F) Kelvin (K) Rankine (°R)
Example: 0°C = 32°F = 273.15 K
Open ConverterScientific Unit Converter
Convert between scientific units across 11 categories. Free, instant, no account required.
Concentration
Convert between molar, millimolar, micromolar, nanomolar, molal, ppm, ppb, and percent w/v concentration units.
Molar (M) Millimolar (mM) Micromolar (μM) Nanomolar (nM) Molal (m) Parts per Million (ppm) Parts per Billion (ppb) Percent w/v (% w/v)
Example: 1 M = 1000 mM = 1,000,000 μM
Open ConverterEnergy
Convert between joules, kilojoules, calories, kilocalories, electron volts, and more energy units.
Joule (J) Kilojoule (kJ) Calorie (cal) Kilocalorie (kcal) Electron Volt (eV) Watt-hour (Wh) Kilowatt-hour (kWh) Erg
Example: 1 kcal = 4184 J = 4.184 kJ
Open ConverterLength
Convert between metric and imperial length units including nanometre, micrometre, millimetre, centimetre, metre, kilometre, inch, foot, and mile.
Nanometre (nm) Micrometre (μm) Millimetre (mm) Centimetre (cm) Metre (m) Kilometre (km) Inch (in) Foot (ft) Yard (yd) Mile (mi)
Example: 1 m = 100 cm = 1000 mm = 1,000,000 μm
Open ConverterMass
Convert between microgram, milligram, gram, kilogram, metric tonne, ounce, and pound mass units.
Microgram (μg) Milligram (mg) Gram (g) Kilogram (kg) Metric Tonne (t) Atomic Mass Unit (u) Ounce (oz) Pound (lb)
Example: 1 kg = 1000 g = 1,000,000 mg
Open ConverterPressure
Convert between pascal, kilopascal, megapascal, bar, atmosphere, mmHg (torr), and psi pressure units.
Pascal (Pa) Kilopascal (kPa) Megapascal (MPa) Bar Atmosphere (atm) mmHg / Torr PSI
Example: 1 atm = 101325 Pa = 760 mmHg
Open ConverterVolume
Convert between microlitre, millilitre, centilitre, litre, cubic metre, fluid ounce, cup, pint, quart, and gallon volume units.
Microlitre (μL) Millilitre (mL) Centilitre (cL) Litre (L) Cubic Metre (m³) Fluid Ounce (fl oz) Cup Pint (pt) Quart (qt) Gallon (gal)
Example: 1 L = 1000 mL = 1,000,000 μL
Open ConverterTime
Convert between nanosecond, microsecond, millisecond, second, minute, hour, day, week, month, and year time units.
Nanosecond (ns) Microsecond (μs) Millisecond (ms) Second (s) Minute (min) Hour (h) Day Week Month Year
Example: 1 hour = 60 minutes = 3600 seconds
Open ConverterRadioactivity
Convert between becquerel, kilobecquerel, megabecquerel, gigabecquerel, curie, millicurie, and microcurie radioactivity units.
Becquerel (Bq) Kilobecquerel (kBq) Megabecquerel (MBq) Gigabecquerel (GBq) Curie (Ci) Millicurie (mCi) Microcurie (μCi)
Example: 1 Ci = 3.7 × 10¹⁰ Bq
Open ConverterAtomic Length
Convert between picometres, ångströms, nanometres, Bohr radii, and femtometres — units commonly used in atomic and molecular physics.
Picometre (pm) Ångström (Å) Nanometre (nm) Bohr Radius (a₀) Femtometre (fm)
Example: 1 Å = 100 pm = 0.1 nm
Open ConverterAmount of Substance
Convert between mole, millimole, micromole, nanomole, picomole, and femtomole — essential for chemistry and biochemistry calculations.
Mole (mol) Millimole (mmol) Micromole (μmol) Nanomole (nmol) Picomole (pmol) Femtomole (fmol)
Example: 1 mol = 1000 mmol = 6.022 × 10²³ particles
Open ConverterFrequently Asked Questions
What unit conversions are available?
Periodic Table Online's unit converter supports 11 categories: Temperature, Concentration, Energy, Length, Mass, Pressure, Volume, Time, Radioactivity, Atomic Length, and Amount of Substance.
How do I convert Celsius to Fahrenheit?
Use the Temperature converter. The formula is °F = (°C × 9/5) + 32. For example, 100°C = 212°F.
How do I convert molar to millimolar?
1 Molar (M) = 1000 Millimolar (mM). Use the Concentration converter to convert between M, mM, μM, nM, ppm, ppb, and other concentration units.
What is an ångström in nanometres?
1 ångström (Å) = 0.1 nanometres (nm) = 100 picometres (pm). Use the Atomic Length converter for atomic and molecular scale conversions.