Molecular Weight Calculator
FREE TOOL
Common Reagents (click to load):
Supports: parentheses
(Ca3(PO4)2), hydrates Na2SO4·10H2O or Na2SO4.10H2O
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Molecular Weight Result
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g/mol
| Element | Count | Atomic Weight | Contribution | % Mass |
|---|
How to Use the Molecular Weight Calculator
Type any chemical formula into the input field and click Calculate MW. The calculator parses the formula, identifies all elements, and sums their atomic weights. Use the quick preset buttons to load common lab reagents instantly.
Formula Input Rules
Standard formulas
Use standard chemical notation:
H2O, NaCl, C6H12O6. Capital letter starts each element symbol, lowercase continues it.Parentheses
Parentheses are supported with multipliers:
Ca3(PO4)2, Al2(SO4)3, Fe2(SO4)3. Nested parentheses also work.Hydrates
Use
· or . for water of crystallisation: CuSO4·5H2O, Na2SO4.10H2O, MgSO4·7H2O (Epsom salt).Case matters
Co = Cobalt, CO = Carbon + Oxygen. Always use correct capitalisation: Ca not CA, Mg not MG.About Molecular Weight in the Laboratory
Molecular weight (MW), also called molar mass, is the mass of one mole of a substance in grams. It is fundamental to virtually all quantitative laboratory work — preparing molar solutions, calculating reaction stoichiometry, designing PCR primers and expressing protein concentrations.
Common Lab Reagent Molecular Weights
NaCl — 58.44 g/mol
Sodium chloride. Used in PBS, saline, electrophoresis buffers. 0.9% w/v = 154 mM physiological saline.
Tris Base — 121.14 g/mol
Trisaminomethane. Key component of Tris-HCl buffer, TE buffer, TAE and TBE electrophoresis buffers.
EDTA·2Na — 372.24 g/mol
Disodium EDTA dihydrate. Chelating agent in TE buffer and DNA extraction. Always use disodium form (soluble at pH 8.0).
SDS — 288.38 g/mol
Sodium dodecyl sulphate (C12H25NaO4S). Used in SDS-PAGE. Typically prepared as 10% w/v stock solution.
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