June 06, 2025 | UR Gate

Mole Ratio Calculator – Balance and Find Mole Ratios in Reactions

Easily calculate mole ratios between reactants and products in a chemical equation. Enter an equation using → or = and select compounds to get accurate stoichiometric ratios.

The Mole Ratio Calculator helps you quickly determine the mole ratio between any two substances in a chemical reaction. Whether you're balancing reactions or working on stoichiometry problems, this tool simplifies the process by accepting either → or = as reaction separators. Just enter your equation, select the compounds, and instantly see the exact mole ratio with optional step-by-step analysis.

Mole Ratio Calculator

Note: Enter a balanced chemical equation. You can use either = or → to separate reactants and products.
Example: 2H2 + O2 = 2H2O

How to Use the Mole Ratio Calculator

Enter the Chemical Equation: Type your balanced chemical equation into the input field. The tool supports standard chemical formulas (e.g., H2O, Fe2O3) and coefficients (e.g., 2H2).
Separate Reactants and Products: Use either an equals sign (=) or an arrow (→) to separate the reactants from the products.
Select Compounds: Once you enter a valid equation, the dropdown menus below will automatically populate with the compounds from your equation. Select the two compounds you wish to find the mole ratio for.
Calculate: Click the "Calculate Ratio" button. The tool will display the simplified mole ratio between the two selected compounds.

Understanding Mole Ratios in Chemistry

A mole ratio is a conversion factor derived from the coefficients of a balanced chemical equation. These coefficients represent the number of moles of each substance involved in the reaction. The mole ratio is fundamental in stoichiometry as it allows chemists to calculate the amount of a reactant needed or a product formed in a chemical reaction.

For example, in the reaction 2H2 + O2 → 2H2O, the mole ratio between hydrogen (H2) and water (H2O) is 2:2, which simplifies to 1:1. This means that for every 2 moles of hydrogen consumed, 2 moles of water are produced.

Examples of Mole Ratio Calculations

Synthesis of Ammonia: N2 + 3H2 → 2NH3
The mole ratio of N2 to NH3 is 1:2.
Combustion of Methane: CH4 + 2O2 → CO2 + 2H2O
The mole ratio of O2 to H2O is 2:2 or 1:1.
Photosynthesis: 6CO2 + 6H2O → C6H12O6 + 6O2
The mole ratio of CO2 to C6H12O6 is 6:1.

Frequently Asked Questions (FAQ)

Q: What happens if my equation isn't balanced?

A: This calculator determines the ratio based on the coefficients you provide. If the equation is unbalanced, the calculated ratio will reflect the incorrect coefficients. For chemically accurate results, always use a balanced equation.

Q: Why is the ratio simplified?

A: The ratio is simplified to its lowest whole-number terms (e.g., 2:4 becomes 1:2) because this represents the most fundamental relationship between the amounts of the substances, which is the standard convention in chemistry.

Q: Can I use this tool for limiting reactant problems?

A: Yes! Finding the mole ratio is the crucial first step in solving most stoichiometry problems, including identifying the limiting reactant. This tool helps you establish the correct stoichiometric relationship needed for further calculations.