ChemBench

Percent Yield Calculator

How close did the reaction get to perfect?

Reality vs. the theoretical maximum

Percent yield compares what you actually collected in the lab (actual yield) to what stoichiometry predicts is the maximum possible (theoretical yield) — real reactions almost never hit 100% due to side reactions, incomplete reactions, or product lost during purification.

Why it's a key lab metric

Percent yield is one of the standard ways chemistry labs and industrial processes are graded — a consistently low yield signals a technique or process problem worth investigating.

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ChemBench

Percent Yield Calculator

How close did the reaction get to perfect?

Actual yield (g)

Theoretical yield (g)

Percent yield

90 %

% yield = actual ÷ theoretical × 100

What you entered

Actual yield (g): 18Theoretical yield (g): 20

1
Percent yield = actual ÷ theoretical × 100
18 ÷ 20 × 100= 90%

Result

Percent yield: 90 %

Getting 18g out of a theoretical 20g is a 90% yield.

Reality vs. the theoretical maximum

Why it's a key lab metric

Percent yield is one of the standard ways chemistry labs and industrial processes are graded — a consistently low yield signals a technique or process problem worth investigating.