Percent Yield Calculator

Percent yield = (actual / theoretical) × 100. Quantifies reaction efficiency.

Inputs

Result

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How to use this calculator

  • Enter both yields in matching units.
  • Read percent yield.

About this calculator

Reactions don't always give 100% of the theoretical product — some is lost to side reactions, transfers, evaporation, or incomplete conversion. Percent yield = (actual product / theoretical product) × 100. Below 50% suggests a problem; above 100% means measurement error or contamination.

Frequently asked

Can yield exceed 100%?+
Mathematically yes if there's contamination, residual solvent, or weighing error. A "yield" >100% is a red flag for cleanup or measurement issues.
What's a good yield?+
Depends on the reaction class. Simple precipitations: 95%+. Multi-step organic synthesis: 60-80%. Total synthesis of complex natural products: <20% over many steps is common.
How to improve yield?+
Reduce side reactions (lower temperature, control stoichiometry), minimize transfer losses, ensure complete conversion (longer reaction time or excess reagent on what's cheap).
Yield in moles or grams?+
Either, as long as both numbers use the same unit. Mole-basis is more meaningful for comparing different products.
Theoretical yield from limiting reactant?+
Use the limiting-reactant calculator to find moles of product, then convert to grams via molar mass.

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