Calculate the percent yield of a chemical reaction. Enter the actual yield you collected and the theoretical yield you calculated, in the same unit. Free, private, and runs entirely in your browser.
Percent yield compares what you actually collected with the most the reaction could produce. Divide the actual yield by the theoretical yield and multiply by 100.
What is theoretical yield? It is the maximum amount of product the reaction can make, calculated from the balanced equation and the limiting reactant.
Can percent yield be over 100%? Not in a perfect reaction. Values over 100% usually mean that the product is wet or impure, or that there was a measuring error.
A reaction should give 10.0 g of product, and you collect 8.2 g. Percent yield = 8.2 ÷ 10.0 × 100 = 82%, and 1.8 g was not recovered.
What is a good percent yield? It depends on the reaction. Simple reactions can reach 90% or more, while multi-step syntheses are often much lower.
Why is the yield below 100%? Side reactions, incomplete reactions and losses while filtering, transferring or purifying all reduce the amount you recover.
The calculation of how much product a reaction should give rests on stoichiometry, a term coined by the German chemist Jeremias Benjamin Richter in the 1790s. His work on the fixed proportions in which substances combine became the basis for balanced equations and theoretical yields, the quantity that percent yield is measured against.
Use this calculator for chemistry labs, process chemistry and any reaction where you compare the product you got with the maximum possible. A lab that gives 4.35 g from a theoretical 5.00 g has a percent yield of 87%. Report your yield together with how you dried and weighed the product.
How do I find the theoretical yield? Convert the limiting reactant to moles, use the mole ratio from the balanced equation, and convert the moles of product to grams.
How do I find the actual yield from a percent yield? Multiply the theoretical yield by the percent yield divided by 100.