Theoretical Yield Calculator | Compute theoretical yield

Formula: Theoretical yield = moles of limiting reactant × mole ratio × molar mass of product

How the result is calculated

Theoretical yield is the most product a reaction can make if every bit of the limiting reactant converts perfectly. You convert the limiting reactant to moles, scale by the balanced mole ratio, then convert product moles back to mass.

1. Balance the equation and convert each reactant’s mass to moles (mass ÷ molar mass).
2. Find the limiting reactant — the one that produces the least product.
3. Multiply its moles by the product:reactant mole ratio, then by the product’s molar mass.

Example

4.0 g H₂ (2.0 mol) with excess O₂ forming H₂O (ratio 2:2): 2.0 mol H₂O × 18.02 g/mol = 36.0 g theoretical yield of water.

What is the Theoretical Yield Calculator?

The Theoretical Yield Calculator is a free, browser-based math calculator tool that helps you Theoretical Yield Calculator is a free online calculator that helps you work out theoretical yield quickly and accurately, right in your browser.. Instead of working through the math by hand or in a spreadsheet, you enter your values and the calculator returns an accurate result instantly — while still showing the formula and the steps so you can verify the reasoning. It is designed for quick everyday use: no sign-up, no installation, and everything runs locally in your browser for complete privacy.

How to use the Theoretical Yield Calculator

1. Enter the required values into the input fields.
2. Press the calculate button — the result appears immediately, updated live as you change any value.
3. Read the step-by-step breakdown below the result to see exactly how the calculation was performed.
4. Use the interpretation guide to understand what the result means for your situation, and try different inputs to see how they change the outcome.

How to use the Theoretical Yield Calculator

Enter the masses of the reactants and the coefficients from your balanced equation, and the tool identifies the limiting reactant and computes the theoretical yield: moles of limiting reactant × mole ratio × molar mass of product. Enter the reactant masses and balanced-equation coefficients and the tool does the mole conversions and ratio for you, returning the maximum product mass possible in grams.

Interpreting your result

The theoretical yield is the maximum product mass a reaction can produce assuming perfect conversion of the limiting reactant — the reactant that runs out first. Real reactions always produce less; the percent yield = actual ÷ theoretical × 100 tells you how efficient your procedure was, with typical lab yields of 60–95%. Identifying the limiting reactant is the core skill: convert every reactant to moles, divide by its coefficient, and the smallest result is the limiter. The calculator shows this comparison so you can see which reactant constrains the reaction.

Common mistakes to avoid

The most common error is skipping the limiting-reactant step and using the reactant with the most mass — mass is not moles, and the coefficient matters. Second, using an unbalanced equation: the mole ratios are meaningless without correct coefficients. Third, mixing grams and moles in the ratio step. Finally, reporting a percent yield above 100% without investigating — it usually means the product was wet, impure, or the weighing was off.

Tips for best results

Balance the equation first and write down the mole ratios. Convert all reactant masses to moles before comparing. Identify the limiting reactant explicitly — it decides everything downstream. Convert the limiting moles to product using the mole ratio, then to grams with the product's molar mass. Compare your actual yield against the theoretical to compute percent yield, and aim to improve it by controlling temperature, time, and purification losses.

Authoritative source: Wolfram MathWorld