Percent Yield Calculator
Calculate percent yield to see how efficient your chemical reaction was. Enter the actual yield from your experiment and the theoretical yield from stoichiometry, and this calculator gives you the percentage plus an efficiency rating.
Percent yield is the single most common way to report how well a reaction performed. It compares what you actually got to what you could have gotten under perfect conditions.
The Formula
% yield = (actual yield / theoretical yield) x 100
Quick Example
You ran a synthesis and collected 8 g of product. Stoichiometry says the maximum was 10 g.
% yield = (8 / 10) x 100 = 80%
That is a good yield for most organic reactions.
Rearranged Forms
- Actual yield = (% yield / 100) x theoretical yield
- Theoretical yield = (actual yield / % yield) x 100
What Counts as a Good Yield?
| Range | Rating | Typical Context |
|---|---|---|
| 90%+ | Excellent | Simple inorganic reactions |
| 70-89% | Good | Many organic syntheses |
| 50-69% | Moderate | Multi-step reactions |
| <50% | Low | Complex natural product synthesis |
Why Yields Fall Below 100%
Side reactions consume reactants, products stick to glassware during transfer, purification steps like recrystallization always lose some product, and incomplete reactions leave unreacted starting material behind.