Stoichiometry Calculator

How Stoichiometry Works

Stoichiometry is the calculation of reactants and products in chemical reactions using the balanced equation and mole ratios. It allows you to determine how much of a product is formed from a given amount of reactant, or how much reactant is needed.

Enter a chemical equation, specify the known substance and amount, and choose the target substance. The calculator will balance the equation, apply mole ratios, and show each conversion step.

The Stoichiometry Process

Stoichiometric calculations follow a consistent set of steps. First, the chemical equation must be balanced so the mole ratios between reactants and products are known. Then, the given quantity is converted to moles (if not already in moles), the mole ratio from the balanced equation is applied to find moles of the target substance, and finally the result is converted to the desired unit.

For example, to find how many grams of water are produced from 4 grams of hydrogen gas: 2H2 + O2 → 2H2O. Convert 4 g H2 to moles (4 ÷ 2.016 = 1.98 mol), apply the 2:2 mole ratio to get 1.98 mol H2O, then convert to grams (1.98 × 18.015 = 35.7 g H2O).

Supported Units

• Grams (g): The most common laboratory unit for mass.
• Moles (mol): The SI unit for amount of substance, central to all stoichiometric conversions.
• Kilograms (kg) and Milligrams (mg): For industrial-scale or micro-scale calculations.
• Liters (L): For gas volumes at standard temperature and pressure (STP), where 1 mole of an ideal gas occupies 22.414 L.

Step-by-Step Solutions

This calculator shows every conversion step in detail, including the balanced equation, molar masses used, mole ratio applied, and unit conversions performed. This makes it an effective learning tool for understanding the stoichiometric method, not just getting an answer.