📊 Percent Yield Calculator

How to Use This Calculator

Choose which quantity you want to find, then enter the two known values. The calculator solves for percent yield, actual yield, or theoretical yield depending on your selection. All masses are in grams and percent yield is a percentage.

Percent Yield Formula

Theoretical yield is the mass of product you would get if every mole of the limiting reagent converted completely into product with no losses. Actual yield is what you physically collect and weigh at the end of the experiment. Dividing the actual by the theoretical and multiplying by 100 gives percent yield. A result of 75% means you collected three-quarters of the maximum possible amount.

Worked Examples

Where This Calculation Comes Up

Percent yield is one of the first things your instructor asks for in every synthesis lab report. After you run an experiment, weigh your product, and compare it to the stoichiometric prediction, percent yield gives a single number that summarises how well the reaction went. A yield of 85% is considered good for a multi-step organic synthesis. A yield of 50% would prompt you to think about what went wrong: did you lose product during filtration, did a side reaction occur, or was your starting material impure?

In pharmaceutical manufacturing, percent yield has direct financial consequences. Active drug ingredients are expensive to synthesise, and a process with 60% yield wastes 40% of the raw material in every batch. Process chemists spend months optimising reaction conditions, temperature, solvent choice, and reaction time to push yield as high as possible, sometimes from 60% to 90%, which can save millions of dollars per year in a large-scale production setting. Even in research, reporting yield is standard: a journal article describing a new synthesis will always state the percent yield so other chemists can judge whether the method is practical.