A stoichiometry calculator uses a balanced chemical equation to find how much of each substance reacts or forms. It converts between grams, moles and particles, identifies the limiting reactant and calculates the theoretical yield, showing each step so you can learn the process.
The basic path is grams → moles → moles → grams. First, convert the given mass to moles using molar mass. Then use the mole ratio from the balanced equation. Finally, convert to grams of the target substance. For example, in 2H₂ + O₂ → 2H₂O, how much water forms from 8.0 g of H₂? Moles of H₂ = 8.0 ÷ 2.016 ≈ 3.97 mol. The ratio of H₂ to H₂O is 2:2, so 3.97 mol of water forms. Multiply by 18.02 g/mol to get about 71.5 g.
When two reactants are given, find the limiting reactant: calculate how much product each could make, and the one that makes less is limiting. The other is in excess. The theoretical yield is the amount of product the limiting reactant can produce.
Common mistakes: not balancing the equation first, using the wrong molar mass, and mixing up mole ratios. Keep track of units and significant figures at every step. Real experiments produce less than the theoretical yield, which is why percent yield calculations are important.
Why use an online Stoichiometry Calculator: it saves time, avoids simple arithmetic mistakes and shows each step, so you can check your homework, plan a project or make a decision with confidence. Bookmark the page so it’s ready the next time you need it.
Tips for getting accurate results from the Stoichiometry Calculator: double-check that every input uses the right units, enter numbers without commas or symbols, and run the calculation a second time with a quick estimate in your head to confirm the answer looks reasonable.
Learn more on Wikipedia’s stoichiometry article. Find percent yield, balancing equations and net ionic equation calculators on Minedit.