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Empirical Formula Calculator

Find the simplest whole-number ratio of atoms in a compound from each element’s mass percent or mass.
Use element symbols (C, H, O...) and mass percent or mass in grams.
Empirical formula
CH2O
Common multiplier
×1
Smallest mole value
3,33 mol
C moles
3,33 (ratio 1)
H moles
6,647 (ratio 1,996)
O moles
3,331 (ratio 1)
25%
50%
25%
C
H
O
Atom ratio in the empirical formula
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Miten tämä laskin toimii?

Convert each element’s mass percent (or grams) to moles by dividing by its atomic weight, divide every result by the smallest mole value to get ratios, then scale by a small integer until all values are whole numbers. Those integers are the subscripts of the empirical formula, the simplest atom ratio in the compound.

Kaava
moles = mass% / atomic weight; ratio = moles / smallest moles; scale to whole numbers
How this is calculated

Enter one element per line as "Element,percent" (for example C,40.0). The percent column may be a mass percentage that sums to about 100, or an actual mass in grams — the math is identical because the ratios are unaffected by a constant scale factor. Each symbol is matched to its standard atomic weight.

For every element the calculator divides its mass (or percent) by its atomic weight to obtain a relative number of moles. All mole values are then divided by the smallest mole value, giving ratios where the least-abundant element becomes 1. If these ratios are not yet close to whole numbers, the set is multiplied by successive small integers (2 through 6) until every value rounds to an integer within tolerance — this resolves cases like 1.5 (×2) or 1.33 (×3).

The rounded integers become the subscripts of the empirical formula. Note this gives the simplest ratio, not necessarily the molecular formula: glucose (C6H12O6) and formaldehyde (CH2O) share the empirical formula CH2O. Inputs must use valid element symbols and positive amounts; unrecognized symbols or non-positive values are rejected.

Usein kysytyt kysymykset

The empirical formula is the simplest whole-number ratio of atoms, while the molecular formula gives the actual count per molecule. Multiply the empirical formula by molar mass / empirical mass to get the molecular formula.

Yes. Because every value is later scaled relative to the smallest, using grams or mass percent produces the same ratios and the same empirical formula.

When dividing by the smallest mole value yields fractions such as 1.5 or 1.33, the whole set is multiplied by the smallest integer that makes every value a near-integer, preserving the correct ratio.

Tunnetaan myös nimellä

empiirinen kaava
kaava prosenteista
moolisuhde
yksinkertaisin kaava
suhdekaava
empirical formula
formula from percent
mole ratio

APA

TG we-Calculate Editorial Team. (2026). Empirical Formula Calculator [Online calculator]. TG we-Calculate. https://we-calculate.com/fi/calculator/empirical-formula-calculator

Chicago

TG we-Calculate Editorial Team. "Empirical Formula Calculator." TG we-Calculate. 2026. https://we-calculate.com/fi/calculator/empirical-formula-calculator.

IEEE

TG we-Calculate Editorial Team, "Empirical Formula Calculator," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/fi/calculator/empirical-formula-calculator

BibTeX

@misc{wecalculate_empirical_formula_calculator, title = {Empirical Formula Calculator}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/fi/calculator/empirical-formula-calculator}}, year = {2026}, note = {TG we-Calculate} }

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