Percent Yield Calculator
Calculate the efficiency of chemical reactions by comparing actual yield to theoretical yield.
Input Values
Actual Yield
The actual amount obtained from your experiment
Theoretical Yield
The calculated maximum amount possible
Choose how many decimal places to show
Calculation Results
Error
Percent Yield
Yield Result
Percent Yield in Chemistry
Every chemistry experiment aims for perfection, but the real world often falls short. That's where percent yield comes in - it measures how close you got to that ideal result. This calculator helps you figure out exactly what percentage of your theoretical maximum you actually achieved.
The concept is straightforward: you take what you actually produced in your experiment and divide it by what you calculated should be possible under perfect conditions. Multiply by 100, and you have your percent yield. A result of 100% means everything went perfectly. Less than that? Well, that's chemistry for you.
How Percent Yield Works
Percent yield tells you about the efficiency of your reaction. If you get 80%, that means 20% of your starting materials ended up somewhere else - maybe lost during transfer, not fully reacted, or tied up in side reactions. Understanding this helps you improve your technique and get better results next time.
The Formula
This is the standard formula used in all chemistry labs and textbooks.
Example Calculations
| Actual Yield | Theoretical Yield | Percent Yield | Efficiency |
|---|---|---|---|
| 40 g | 50 g | 80% | Good |
| 25 g | 25 g | 100% | Perfect |
| 18 g | 30 g | 60% | Fair |
| 9 g | 15 g | 60% | Fair |
| 35 g | 40 g | 87.5% | Good |
| 12 g | 20 g | 60% | Fair |
| 45 g | 50 g | 90% | Excellent |
| 8 g | 10 g | 80% | Good |
| 22 g | 25 g | 88% | Good |
| 15 g | 30 g | 50% | Fair |
| 28 g | 35 g | 80% | Good |
| 6 g | 12 g | 50% | Fair |
| 42 g | 45 g | 93.3% | Excellent |
| 11 g | 22 g | 50% | Fair |
| 33 g | 40 g | 82.5% | Good |
| 7 g | 14 g | 50% | Fair |
| 38 g | 42 g | 90.5% | Excellent |
| 14 g | 25 g | 56% | Fair |
| 29 g | 32 g | 90.6% | Excellent |
| 5 g | 8 g | 62.5% | Fair |
| 47 g | 55 g | 85.5% | Good |
| 16 g | 28 g | 57.1% | Fair |
| 21 g | 24 g | 87.5% | Good |
| 3 g | 6 g | 50% | Fair |
| 36 g | 38 g | 94.7% | Excellent |
| 13 g | 26 g | 50% | Fair |
As you can see from the table, yields can vary widely. The first row shows a solid 80% yield - pretty good for most reactions. The second row is perfect at 100%, which is rare but possible. The last two show 60% yields, which might indicate room for improvement in the experimental procedure.
Different types of reactions have different typical yields. Some organic syntheses might aim for 70-90%, while others might be satisfied with 50%. What's important is consistency and understanding why your yield is what it is.
This calculator supports all common units: grams (g), milligrams (mg), kilograms (kg), and moles (mol). Just make sure both your actual and theoretical yields use the same unit - the calculator will remind you if you try to mix them.