Molecular Weight Calculator

Molecular Weight Calculator

Enter a chemical formula (e.g., H2O, NaCl, C6H12O6). The calculator will compute its molecular weight.

`; return; } const weight = atomicWeights[part.element] * part.count; totalWeight += weight; steps.push(`${part.count} × ${part.element} (${atomicWeights[part.element]}) = ${weight.toFixed(3)}`); } el('mw-results').innerHTML = `

Result

${totalWeight.toFixed(3)} g/mol

Steps

${steps.map(s=>""+s+"").join("")}
`; } function reset(){ el('mw-formula').value = ''; el('mw-results').innerHTML = ''; } return { calculate, reset }; })();

Molecular Weight Calculator

A Molecular Weight Calculator is a tool used to calculate the molecular weight (molar mass) of a chemical compound based on its chemical formula. Molecular weight is the sum of the atomic weights of all atoms present in a molecule and is typically expressed in grams per mole (g/mol).

This calculator is widely used in chemistry, biochemistry, pharmaceuticals, environmental science, and laboratory work to ensure accurate measurements and correct chemical reactions. You might also be interested in a weight conversion calculator

How the Molecular Weight Calculator Works

The calculator analyzes the chemical formula you enter and:

  1. Identifies each element in the compound
  2. Determines the number of atoms of each element
  3. Retrieves the standard atomic weight for each element
  4. Adds all atomic contributions to produce the total molecular weight

Example:

H₂O

Hydrogen (H): 2 × 1.008
Oxygen (O): 1 × 15.999

Molecular weight = 18.015 g/mol

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Why Molecular Weight Is Important

Knowing the molecular weight of a compound helps you:

  • Convert between mass and moles
  • Prepare accurate chemical solutions
  • Balance chemical equations
  • Perform stoichiometric calculations
  • Analyze reactions in laboratory experiments

Key Features of the Molecular Weight Calculator

  • Supports simple and complex chemical formulas
  • Uses standard atomic weights for accuracy
  • Handles subscripts and multiple elements
  • Provides fast and reliable results
  • Suitable for students, teachers, and professionals

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Who Should Use a Molecular Weight Calculator?

  • Chemistry students and educators
  • Laboratory technicians
  • Researchers and scientists
  • Pharmaceutical and industrial chemists
  • Anyone working with chemical compounds

Common Applications

  • Calculating molar mass for solution preparation
  • Determining reactant quantities in reactions
  • Academic homework and exam preparation
  • Quality control in chemical manufacturing

Get Accurate Molecular Weights Instantly

Instead of manually adding atomic masses, use the Molecular Weight Calculator to get precise results instantly. It’s a simple and reliable way to calculate molar mass and work confidently with chemical formulas.

Note: Atomic weights are standard atomic weights (average values). They may vary slightly depending on isotopes, but these are the commonly accepted values used in education.

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Table of Atomic Elements and Atomic Weights

Atomic No. Element Name Symbol Atomic Weight
1 Hydrogen H 1.008
2 Helium He 4.0026
3 Lithium Li 6.94
4 Beryllium Be 9.0122
5 Boron B 10.81
6 Carbon C 12.011
7 Nitrogen N 14.007
8 Oxygen O 15.999
9 Fluorine F 18.998
10 Neon Ne 20.180
11 Sodium Na 22.990
12 Magnesium Mg 24.305
13 Aluminum Al 26.982
14 Silicon Si 28.085
15 Phosphorus P 30.974
16 Sulfur S 32.06
17 Chlorine Cl 35.45
18 Argon Ar 39.948
19 Potassium K 39.098
20 Calcium Ca 40.078
21 Scandium Sc 44.956
22 Titanium Ti 47.867
23 Vanadium V 50.942
24 Chromium Cr 51.996
25 Manganese Mn 54.938
26 Iron Fe 55.845
27 Cobalt Co 58.933
28 Nickel Ni 58.693
29 Copper Cu 63.546
30 Zinc Zn 65.38
31 Gallium Ga 69.723
32 Germanium Ge 72.630
33 Arsenic As 74.922
34 Selenium Se 78.971
35 Bromine Br 79.904
36 Krypton Kr 83.798
37 Rubidium Rb 85.468
38 Strontium Sr 87.62
39 Yttrium Y 88.906
40 Zirconium Zr 91.224
41 Niobium Nb 92.906
42 Molybdenum Mo 95.95
43 Technetium Tc 98
44 Ruthenium Ru 101.07
45 Rhodium Rh 102.91
46 Palladium Pd 106.42
47 Silver Ag 107.87
48 Cadmium Cd 112.41
49 Indium In 114.82
50 Tin Sn 118.71
51 Antimony Sb 121.76
52 Tellurium Te 127.60
53 Iodine I 126.90
54 Xenon Xe 131.29
55 Cesium Cs 132.91
56 Barium Ba 137.33
57 Lanthanum La 138.91
58 Cerium Ce 140.12
59 Praseodymium Pr 140.91
60 Neodymium Nd 144.24
61 Promethium Pm 145
62 Samarium Sm 150.36
63 Europium Eu 151.96
64 Gadolinium Gd 157.25
65 Terbium Tb 158.93
66 Dysprosium Dy 162.50
67 Holmium Ho 164.93
68 Erbium Er 167.26
69 Thulium Tm 168.93
70 Ytterbium Yb 173.05
71 Lutetium Lu 174.97
72 Hafnium Hf 178.49
73 Tantalum Ta 180.95
74 Tungsten W 183.84
75 Rhenium Re 186.21
76 Osmium Os 190.23
77 Iridium Ir 192.22
78 Platinum Pt 195.08
79 Gold Au 196.97
80 Mercury Hg 200.59
81 Thallium Tl 204.38
82 Lead Pb 207.2
83 Bismuth Bi 208.98
84 Polonium Po 209
85 Astatine At 210
86 Radon Rn 222
87 Francium Fr 223
88 Radium Ra 226
89 Actinium Ac 227
90 Thorium Th 232.04
91 Protactinium Pa 231.04
92 Uranium U 238.03
93 Neptunium Np 237
94 Plutonium Pu 244
95 Americium Am 243
96 Curium Cm 247
97 Berkelium Bk 247
98 Californium Cf 251
99 Einsteinium Es 252
100 Fermium Fm 257
101 Mendelevium Md 258
102 Nobelium No 259
103 Lawrencium Lr 266
104 Rutherfordium Rf 267
105 Dubnium Db 268
106 Seaborgium Sg 269
107 Bohrium Bh 270
108 Hassium Hs 277
109 Meitnerium Mt 278
110 Darmstadtium Ds 281
111 Roentgenium Rg 282
112 Copernicium Cn 285
113 Nihonium Nh 286
114 Flerovium Fl 289
115 Moscovium Mc 290
116 Livermorium Lv 293
117 Tennessine Ts 294
118 Oganesson Og 294