Theoretical Yield Calculator
Calculate the theoretical yield (maximum possible product mass) from the limiting reagent mass, molar masses and stoichiometric ratio. For education only.
How to use this tool
- Enter mass of limiting reagent, molar mass of limiting reagent, molar mass of product and stoichiometric ratio (mol product / mol reagent) in the fields above.
- Results update instantly as you type — or click Calculate.
- Read your theoretical yield and the full breakdown beneath it.
Theoretical yield is the maximum mass of product assuming 100% conversion of the limiting reagent. Steps: (1) convert reagent mass to moles, (2) multiply by stoichiometric ratio to get product moles, (3) convert to grams using product molar mass.
For education only.
Formula
Step 1: molesLR = massLR ÷ molar massLR
Step 2: molesproduct = molesLR × stoichiometric ratio
Step 3: theoretical yield (g) = molesproduct × molar massproduct
How it works
This calculator converts the mass of the limiting reagent to moles, scales those moles by the stoichiometric ratio (mol product per mol reagent from the balanced equation), then converts back to grams using the product's molar mass — the standard three-step stoichiometry path to theoretical yield.
The stoichiometric ratio must be taken from the balanced chemical equation; for a 1:1 reaction enter 1. Results assume 100 % conversion with no side reactions; actual experimental yields will typically be lower.
Worked example
Worked example: NaCl → AgCl precipitation
- Identify inputs: mass of limiting reagent (NaCl) = 10.0 g, molar mass of NaCl = 58.44 g/mol, molar mass of product (AgCl) = 74.55 g/mol, stoichiometric ratio = 1.0.
- Convert reagent to moles: moles_LR = 10.0 ÷ 58.44 = 0.17112 mol.
- Scale by stoichiometric ratio: moles_product = 0.17112 × 1.0 = 0.17112 mol.
- Convert product moles to grams: theoretical yield = 0.17112 × 74.55 = 12.759 g.
Moles of limiting reagent = 0.17112 mol; Theoretical yield = 12.759 g
Key terms
- Limiting reagent
- The reactant that is completely consumed first, setting the upper limit on how much product can form.
- Stoichiometric ratio
- The mole ratio of product to limiting reagent derived from the coefficients in a balanced chemical equation.
- Theoretical yield
- The maximum mass of product obtainable assuming complete reaction and no losses.
- Molar mass
- Mass of one mole of a substance in g/mol; used to interconvert between mass and moles.
- Balanced equation
- A chemical equation where the number of atoms of each element is equal on both sides, providing the stoichiometric coefficients.
Frequently asked questions
- What is a limiting reagent?
- The reactant that is completely consumed first, limiting how much product can form. Any remaining reactant is in excess.
- Where do I find the stoichiometric ratio?
- From the balanced chemical equation. E.g. 2H₂ + O₂ → 2H₂O means 2 mol H₂ produces 2 mol H₂O, so ratio = 1:1. N₂ + 3H₂ → 2NH₃ means 1 mol N₂ → 2 mol NH₃, ratio = 2.