Calculate theoretical yield from limiting reagent, stoichiometry, and molar masses. Compare reagents, identify excess, and plan synthesis quantities.
The theoretical yield calculator determines the maximum amount of product that can be formed from a given amount of reactants, based on stoichiometry and the limiting reagent. Theoretical yield is the starting point for all yield calculations — it represents perfect, 100% conversion with no losses.
Calculating theoretical yield requires three things: the balanced equation (to get molar ratios), the amounts of each reactant (to identify the limiting reagent), and the product's molar mass (to convert moles to grams). The limiting reagent — the reactant that runs out first — dictates the theoretical yield. Any other reactant is present in excess.
This calculator handles reactions with up to four reactants, identifies the limiting reagent automatically, calculates exact theoretical yield, shows excess amounts of non-limiting reagents, and supports scaling for different batch sizes. Preset reactions demonstrate common synthesis scenarios.
For best results, combine calculator output with direct observation and periodic check-ins with a veterinarian or qualified advisor. Small adjustments made early usually improve comfort, safety, and long-term outcomes more than large corrective changes made later.
This calculator automates the multi-step theoretical yield process: mass-to-moles conversion, limiting reagent identification, stoichiometric calculation, and back-conversion to grams. It shows excess amounts and supports batch scaling. This theoretical yield calculator helps you compare outcomes quickly and reduce avoidable mistakes when making day-to-day care decisions. Use the estimate as a planning baseline and confirm final decisions with a qualified professional when risk is high.
Theoretical Yield = Moles of limiting reagent × (Product coefficient / Limiting reagent coefficient) × Product molar mass\n\nLimiting Reagent: The reactant with the smallest value of (Moles available / Stoichiometric coefficient)\n\nExcess = Available moles − Required moles This keeps planning practical and lowers the chance of preventable errors.
Result: 6.99 g Fe
Fe₂O₃ + 2Al → Al₂O₃ + 2Fe. Moles Fe₂O₃ = 10.0/159.69 = 0.0626. Moles Al = 5.0/26.98 = 0.1853. Ratio test: Fe₂O₃ = 0.0626/1 = 0.0626, Al = 0.1853/2 = 0.0927. Fe₂O₃ is limiting. Yield = 0.0626 × (2/1) × 55.85 = 6.99 g Fe.
In the lab, chemists intentionally use one reagent in excess to drive the reaction toward completion (Le Chatelier's principle). The choice of which reagent to make limiting depends on cost, ease of removal of excess, and safety. Expensive or difficult-to-synthesize reagents are typically the limiting reagent, with a cheap excess of the other.
For sequential reactions A→B→C, the theoretical yield of C depends on the theoretical yield of B, which depends on A. Calculate each step independently: the yield of one step becomes the starting material for the next. The overall theoretical yield is the product of individual theoretical yields divided by the molecular weight.
Scaling reactions from milligrams (research) to kilograms (production) isn't simply multiplication. Heat transfer, mixing efficiency, and mass transfer change with scale. However, the theoretical yield calculation scales linearly — double all reagents, double the theoretical yield. Issues arise in percent yield, not theoretical yield, during scale-up.
Theoretical yield is the maximum mass of product that can be formed from given reactant amounts, assuming the reaction goes to 100% completion with no side reactions or losses. It is calculated from stoichiometry.
Divide the available moles of each reactant by its stoichiometric coefficient. The reactant with the smallest value is the limiting reagent — it will be consumed first.
The excess reagent is not fully consumed. Some remains unreacted after the limiting reagent is used up. The amount of excess is the difference between what's available and what's required by stoichiometry.
Real reactions have imperfect conversion, side reactions, mechanical losses during transfer and purification, and incomplete separation of products. The ratio of actual to theoretical yield is the percent yield.
Yes. Balanced equations often have multiple products. Each product has its own theoretical yield, calculated independently using the same limiting reagent. This calculator focuses on the primary desired product.
Multiply all reactant masses by the same factor to scale a reaction. If you need 10× the product, use 10× of each reactant. The limiting-reagent calculation ensures the ratios stay correct.