Molecular Weight Calculator

Calculate the molecular weight of chemical formulas online, supporting single and batch calculations, with detailed elemental composition analysis

Bug report

Browser execution mode: Your data is processed in your browser and is not uploaded to the server.

Speed and Stability: Processing speed depends on your device and browser. For large batch work, the desktop version may be more stable.

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If the online tool fails to load or run, try the desktop tool.https://tools.yikeaigc.com/

Tool Usage

Return to old version

Set the calculation mode first, then enter a formula or batch data.

Supports parentheses, hydrate dots, common substance lookup, elemental analysis, mole conversion, concentration conversion, empirical formula calculation, and equation balancing.

Local calculation Parentheses & Hydrates CSV / ZIP Export Savable settings

Batch files No files selected

After uploading TXT or CSV files, the first 20 filenames appear here. All files are processed, and results are generated with the original filenames.

Input & Settings

Confirm mass mode and decimal places first, then enter a formula. Examples: H2O, Ca(OH)2, CuSO4·5H2O, C6H12O6.

FormulaCase affects element recognition

Chemical formula

Mass mode

Result decimals

Common substancesAuto-fill after selection

HistoryKeep recent records

Calculation results

Waiting to calculateClick “Calculate” after setup.

Batch calculation

One formula per line. You can also upload multiple TXT / CSV files. The first 20 are shown, but all files are calculated.

Multi-line inputSupports pasting one table column

Formula list

File inputRead locally, not uploaded

Select or drag files Supports .txt, .csv; multiple selection allowed.

Result overviewNot calculated yet

Waiting for batch calculationEnter or upload data first.

Convert and estimate

Set the formula first, then choose a calculation direction. Empirical formula estimation uses element mass percentages; molecular weight is optional.

Molar mass conversionMass, moles, and molecules

Formula

Calculation direction

Mass g

Moles mol

Avogadro's constant

Enter parameters to calculate.

Solution Concentration ConverterMolarity and Weighed Mass

Solute formula

Calculation direction

Solute mass g

Target concentration mol/L

Solution volume mL

Enter parameters to calculate.

Formula ComparisonMolecular Weight and Element Differences

Formula A

Formula B

Enter two formulas to compare.

Empirical Formula CalculatorCalculate by mass percent

Known molecular weight g/mol (optional)

Enter element mass percentages to calculate.

Equation and Element Reference

Enter an unbalanced equation. Use + to separate substances, and = or → to separate sides. Click an element in the periodic table for info; double-click to insert its formula.

Chemical Equation BalancerOutput coefficients, mass ratios, and checks

Equation

Example equation

Enter an equation to balance.

Element detailsClick to view, double-click to insert

Please select an element.

Periodic tableColor by element category

Instructions

Software Usage Instructions

Set calculation parameters: First select average atomic weight or monoisotopic exact mass, and set the number of decimal places for the results.
Enter a molecular formula: Enter chemical formulas such as H2O, Ca(OH)2, or CuSO4·5H2O, paying attention to the capitalization of element symbols.
View composition results: After clicking Calculate, view the molecular weight, number of atoms of each element, atomic weight subtotals, mass percentages, and composition chart.
Batch calculation: Enter one molecular formula per line, or upload a TXT or CSV file; results can be exported as CSV, and multi-file results can be packaged for download.
Use conversion tools: You can convert between mass and moles, convert solution concentrations, compare molecular formulas, and derive empirical formulas.
Balance equations: Separate substances with +, and separate reactants and products with = or →. Click Balance to view coefficients, mass ratios, and the verification table.
Look up elements: Click an element in the periodic table to view its atomic number, Chinese name, atomic weight, and category; double-click to insert it into the molecular formula.

FAQ

A: Element symbols are case-sensitive. For example, CO represents carbon monoxide, while Co represents the element cobalt. Please write element symbols correctly when entering formulas.

A: CuSO4·5H2O and CuSO4.5H2O are supported, as well as parenthesized forms such as CuSO4(H2O)5.

A: Average atomic weight is suitable for general chemical calculations; monoisotopic exact mass is suitable for mass spectrometry, exact mass verification, and similar scenarios.

A: Batch processing will try to keep the original file names. If duplicate names occur, numbers will be appended to the file names to distinguish them, and the files will be packaged as a ZIP for download.

A: You can enter Fe + O2 = Fe2O3 or CH4 + O2 → CO2 + H2O. Use + between substances, and use = or an arrow between the two sides of the reaction.

A: Enter at least the mass percentages of two elements. If a known molecular weight is provided, the tool will further calculate possible molecular formulas.