Molecular Weight Calculator
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How it works
This calculator computes the molecular weight of chemical compounds by parsing the formula and summing the atomic weights of all atoms.
The formula parser recognizes element symbols (case-sensitive) followed by optional numbers indicating the count. For example:
- H2O: 2 Hydrogen atoms (2 × 1.00794) + 1 Oxygen atom (1 × 15.9994) = 18.01528 g/mol
- NaCl: 1 Sodium atom (1 × 22.98976928) + 1 Chlorine atom (1 × 35.453) = 58.44276928 g/mol
Atomic weights are based on IUPAC values with uncertainty decimals removed for simplicity.
Table of Atomic Elements and Weights Atomic Number Element
| Atomic Number | Element Name | Symbol | Atomic Weight (g/mol) |
|---|---|---|---|
| 1 | Hydrogen | H | 1.00794 |
| 2 | Helium | He | 4.002602 |
| 3 | Lithium | Li | 6.941 |
| 4 | Beryllium | Be | 9.012182 |
| 5 | Boron | B | 10.811 |
| 6 | Carbon | C | 12.0107 |
| 7 | Nitrogen | N | 14.0067 |
| 8 | Oxygen | O | 15.9994 |
| 9 | Fluorine | F | 18.9984032 |
| 10 | Neon | Ne | 20.1797 |
| 11 | Sodium | Na | 22.98976928 |
| 12 | Magnesium | Mg | 24.3050 |
| 13 | Aluminum | Al | 26.9815386 |
| 14 | Silicon | Si | 28.0855 |
| 15 | Phosphorus | P | 30.973762 |
| 16 | Sulfur | S | 32.065 |
| 17 | Chlorine | Cl | 35.453 |
| 18 | Argon | Ar | 39.948 |
| 19 | Potassium | K | 39.0983 |
| 20 | Calcium | Ca | 40.078 |
| 21 | Scandium | Sc | 44.955912 |
| 22 | Titanium | Ti | 47.867 |
| 23 | Vanadium | V | 50.9415 |
| 24 | Chromium | Cr | 51.9961 |
| 25 | Manganese | Mn | 54.938045 |
| 26 | Iron | Fe | 55.845 |
| 27 | Cobalt | Co | 58.933195 |
| 28 | Nickel | Ni | 58.6934 |
| 29 | Copper | Cu | 63.546 |
| 30 | Zinc | Zn | 65.409 |
| 31 | Gallium | Ga | 69.723 |
| 32 | Germanium | Ge | 72.64 |
| 33 | Arsenic | As | 74.92160 |
| 34 | Selenium | Se | 78.96 |
| 35 | Bromine | Br | 79.904 |
| 36 | Krypton | Kr | 83.798 |
| 37 | Rubidium | Rb | 85.4678 |
| 38 | Strontium | Sr | 87.62 |
| 39 | Yttrium | Y | 88.90585 |
| 40 | Zirconium | Zr | 91.224 |
| 41 | Niobium | Nb | 92.90638 |
| 42 | Molybdenum | Mo | 95.94 |
| 43 | Technetium | Tc | 98.9063 |
| 44 | Ruthenium | Ru | 101.07 |
| 45 | Rhodium | Rh | 102.90550 |
| 46 | Palladium | Pd | 106.42 |
| 47 | Silver | Ag | 107.8682 |
| 48 | Cadmium | Cd | 112.411 |
| 49 | Indium | In | 114.818 |
| 50 | Tin | Sn | 118.710 |
| 51 | Antimony | Sb | 121.760 |
| 52 | Tellurium | Te | 127.60 |
| 53 | Iodine | I | 126.90447 |
| 54 | Xenon | Xe | 131.293 |
| 55 | Caesium | Cs | 132.9054519 |
| 56 | Barium | Ba | 137.327 |
| 57 | Lanthanum | La | 138.90547 |
| 58 | Cerium | Ce | 140.116 |
| 59 | Praseodymium | Pr | 140.90765 |
| 60 | Neodymium | Nd | 144.242 |
| 61 | Promethium | Pm | 146.9151 |
| 62 | Samarium | Sm | 150.36 |
| 63 | Europium | Eu | 151.964 |
| 64 | Gadolinium | Gd | 157.25 |
| 65 | Terbium | Tb | 158.92535 |
| 66 | Dysprosium | Dy | 162.500 |
| 67 | Holmium | Ho | 164.93032 |
| 68 | Erbium | Er | 167.259 |
| 69 | Thulium | Tm | 168.93421 |
| 70 | Ytterbium | Yb | 173.04 |
| 71 | Lutetium | Lu | 174.967 |
| 72 | Hafnium | Hf | 178.49 |
| 73 | Tantalum | Ta | 180.9479 |
| 74 | Tungsten | W | 183.84 |
| 75 | Rhenium | Re | 186.207 |
| 76 | Osmium | Os | 190.23 |
| 77 | Iridium | Ir | 192.217 |
| 78 | Platinum | Pt | 195.084 |
| 79 | Gold | Au | 196.966569 |
| 80 | Mercury | Hg | 200.59 |
| 81 | Thallium | Tl | 204.3833 |
| 82 | Lead | Pb | 207.2 |
| 83 | Bismuth | Bi | 208.98040 |
| 84 | Polonium | Po | 208.9824 |
| 85 | Astatine | At | 209.9871 |
| 86 | Radon | Rn | 222.0176 |
| 87 | Francium | Fr | 223.0197 |
| 88 | Radium | Ra | 226.0254 |
| 89 | Actinium | Ac | 227.0278 |
| 90 | Thorium | Th | 232.03806 |
| 91 | Protactinium | Pa | 231.03588 |
| 92 | Uranium | U | 238.02891 |
| 93 | Neptunium | Np | 237.0482 |
| 94 | Plutonium | Pu | 244.0642 |
| 95 | Americium | Am | 243.0614 |
| 96 | Curium | Cm | 247.0703 |
| 97 | Berkelium | Bk | 247.0703 |
| 98 | Californium | Cf | 251.0796 |
| 99 | Einsteinium | Es | 252.0829 |
| 100 | Fermium | Fm | 257.0951 |
| 101 | Mendelevium | Md | 258.0986 |
| 102 | Nobelium | No | 259.1009 |
| 103 | Lawrencium | Lr | 260.1053 |
| 104 | Rutherfordium | Rf | 261.1087 |
| 105 | Dubnium | Db | 262.1138 |
| 106 | Seaborgium | Sg | 263.1182 |
| 107 | Bohrium | Bh | 262.1229 |
| 108 | Hassium | Hs | 265 |
| 109 | Meitnerium | Mt | 266 |
| 110 | Darmstadtium | Ds | 269 |
| 111 | Roentgenium | Rg | 272 |
| 112 | Ununbium | Uub | 285 |
| 113 | Ununtrium | Uut | 284 |
| 114 | Ununquadium | Uuq | 289 |
| 115 | Ununpentium | Uup | 288 |
| 116 | Ununhexium | Uuh | 292 |
| 118 | Ununoctium | Uuo | 294 |