Chemistry

Instant, private, and free

Percent Yield Calculator.

Calculate reaction percent yield from actual and theoretical yields.

On-device calculationNo signup
01

Set your values

Results update as you type.

Percent yield: 80 %

Percent yield

80.000000%

Educational arithmetic only. Keep units consistent and use measured or explicitly supplied chemistry inputs; this tool does not infer reaction pathways, property tables, or safety guidance.

Use Cases

Assess Reaction Efficiency

Use the calculator to quickly determine how efficient a chemical reaction is by comparing the actual product obtained to the theoretical maximum.

Example: If you expected 10 grams but got 8 grams, the percent yield is 80%.

Optimize Laboratory Procedures

Identify losses in synthesis or purification steps by calculating percent yield, helping you refine techniques and improve outcomes.

Example: After recrystallization, calculate yield to see if the purification step caused significant loss.

Frequently Asked Questions

What is percent yield in chemistry?
Percent yield is the ratio of the actual yield (what you actually get from a reaction) to the theoretical yield (the maximum possible amount predicted by stoichiometry), multiplied by 100. It indicates the efficiency of a chemical reaction.
How do I use the Percent Yield Calculator?
Enter the actual yield (the amount of product you obtained) and the theoretical yield (the calculated maximum amount) in the same units. The calculator will compute the percent yield by dividing actual by theoretical and multiplying by 100.
What does a percent yield over 100% mean?
A percent yield over 100% suggests that the actual yield is greater than the theoretical yield. This can happen due to experimental errors, such as impurities, incomplete drying, or measurement inaccuracies. It indicates that the result is not pure or the calculation is off.

Tips & Common Mistakes

Tips

  • Ensure both actual and theoretical yields are in the same units (e.g., grams, moles) before calculating.
  • Use the theoretical yield from a balanced chemical equation for accurate results.
  • Percent yield is typically less than 100% due to losses; values above 100% indicate impurities or errors.
  • For precise results, measure actual yield after drying the product to remove solvents or moisture.

Common Mistakes to Avoid

  • Using different units for actual and theoretical yields, leading to incorrect percent yield.
  • Entering the theoretical yield as the actual yield or vice versa, which gives a misleading percentage.
  • Ignoring the need for a balanced equation when calculating theoretical yield, causing an inaccurate baseline.

Last updated: August 13, 2026