Percent Composition Calculator

Calculate percent by mass of an element in a compound.

Elements in Compound

Enter your values above to see the result.

Your Results

Total Molar Mass

Percent Composition

Formula

Step-by-step Solution

About This Calculator

Calculate percent by mass of each element in a compound.

Everything is worked out in your browser as you type, so your figures never leave your device.

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Pro Tips

Results update as you type — change any field to see the effect immediately.

Check that every value uses the same unit before comparing results.

Use the copy button to paste the percent composition figures into a note or spreadsheet.

Nothing is sent to a server, so you can use this with private figures.