Find limiting reactant and theoretical product yield
A theoretical yield calculator finds the maximum selected product that available reactants can form under one balanced equation. Enter each reactant name, available amount in moles, and balanced coefficient. Then enter the desired product coefficient and molar mass. The page compares reaction extents, identifies the limiting reactant, and reports product moles and mass with a visible stoichiometric path.
All reactant amounts use moles so coefficient ratios can be applied directly. Convert measured masses to moles first with the molar mass of each exact reactant form. The result is a theoretical maximum at complete conversion to the selected product. It does not predict actual recovery, equilibrium conversion, selectivity, side products, purity, or material left in equipment.
Use reaction extent to identify the limiting reactant
For each reactant, divide available moles by its balanced coefficient. This gives how many complete stoichiometric reaction extents that reactant can support. The smallest value limits the reaction. Multiply that minimum extent by the desired product coefficient to obtain theoretical product moles, then multiply by product molar mass for grams.
Comparing extent rather than raw moles is essential. Two moles of a reactant with coefficient two support only one extent, the same as one mole of a reactant with coefficient one. If two rows share the smallest extent within the stated numeric tolerance, they tie as stoichiometric limiting reactants. Other rows are excess on the entered basis.
Follow a theoretical yield example
For 2H2 + O2 → 2H2O, suppose 5.0 mol H2 and 2.0 mol O2 are available. Hydrogen supports 5.0/2 = 2.5 extents, while oxygen supports 2.0/1 = 2.0 extents, so O2 limits. Water moles are 2.0 extents × coefficient 2 = 4.0 mol.
Using a water molar mass of 18.01528 g/mol gives 72.06112 g theoretical water. Hydrogen required for two extents is 4.0 mol, leaving 1.0 mol H2 excess in the ideal bookkeeping. The page reports the limiting-basis table so a learner can see why choosing the reactant with fewer raw moles would not always be correct.
Check balanced coefficients, molar masses, and units
The coefficients must come from one correctly balanced equation and the desired product coefficient must use the same scaling. Product molar mass must describe the exact product formula, including waters of hydration when present. Grams, milligrams, and kilograms are true scale conversions of the same calculated mass; they do not change the chemistry or significant figures.
A useful reverse check divides product moles by its coefficient to recover the limiting extent, then multiplies that extent by each reactant coefficient to find the stoichiometric amount consumed. No required amount may exceed the corresponding available amount. If it does, coefficients, moles, or limiting-reactant selection were entered incorrectly.
Ideal-yield limits, laboratory planning, and privacy
Theoretical yield assumes complete conversion, perfect selectivity, no competing reaction, and no work-up loss. Real processes can be limited by equilibrium, kinetics, reagent purity, moisture, mixing, or decomposition. Use actual analytical data and percent yield after an experiment. A calculated quantity is not a safe operating instruction; procedures, hazards, heat, pressure, and waste require qualified review.
The values are calculated in the current browser tab. NexaCurrent does not upload the quantities, formulas, chemical names, element choices, or other information entered here, and no account is needed. Copying is a deliberate action after the answer and working are visible. Refreshing or leaving the page clears the current calculation, so keep a copied result if it is needed for later study.