Chemical Yield calculator.
Calculate the chemical yield (% yield) of any reaction from the actual isolated mass and the theoretical yield derived from the limiting reagent. Results update live as you type — and every session stays in your browser, never on a server.
What is Chemical Yield — and why does it matter?
Chemical yield (% Yield) measures how much of the theoretically possible product was actually isolated in practice, expressed as a percentage. It compares what you got in the flask to what stoichiometry says you should have been able to make — and the gap between the two represents losses from incomplete reaction, side reactions, purification steps, and handling. A high % yield means the reaction has been run efficiently, generating less waste and requiring fewer raw materials per gram of purified product.
The formula
| Symbol | Term | Units |
|---|---|---|
| $\% \text{Yield}$ | Percentage yield | %; ideal = 100% |
| $m_{\text{actual}}$ | Mass of pure, dry product actually isolated | g |
| $m_{\text{theoretical}}$ | Theoretical yield: moles of limiting reagent × stoichiometric ratio × MW of product | g |
Note: % Yield uses the actual isolated mass — a product still in solution or not yet dried is not fully isolated. Theoretical yield assumes 100% conversion with no side reactions. Values above 100% indicate impurity in the product, incomplete drying, or a calculation error.
Typical chemical yield by reaction and context
| Context | Typical % Yield | Reason |
|---|---|---|
| Industrial optimised process | > 90% | Highly optimised conditions, continuous monitoring, minimal handling losses |
| Excellent lab synthesis | 80–95% | Well-optimised procedure, clean reaction, efficient isolation |
| Good undergraduate result | 60–80% | Good technique; some losses from transfer, recrystallisation, or drying |
| Moderate / acceptable | 40–60% | Incomplete reaction or significant purification losses; review conditions |
| Poor — needs investigation | < 40% | Major losses from side reactions, poor selectivity, or handling; systematic review required |
Strengths and limitations
Strengths
- Simple, universal metric understood across all levels of chemistry
- Directly reflects experimental skill, procedure quality, and reaction optimisation
- Scales directly to economic and environmental cost per gram of product
- Captures losses from all sources: side reactions, isolation, handling
- Can be tracked across a series of experiments to monitor improvement
Limitations
- Says nothing about atom economy — a high-yield reaction can still waste most of the reactant mass as by-products by design
- Does not capture waste from solvents, auxiliaries, or energy use
- Theoretical yield ignores all by-products, assuming 100% selectivity
- Values > 100% indicate errors (impurity, incomplete drying) — not a real result
- Must be paired with Atom Economy and E-factor for a full green chemistry assessment
Chemical yield in context: complementary green metrics
| Metric | What it measures | Stage |
|---|---|---|
| % Yield | Fraction of theoretical product actually isolated — experimental efficiency | Experimental |
| Atom Economy (AE) | Theoretical fraction of reactant mass incorporated into desired product by design | Design |
| Reaction Mass Efficiency (RME) | AE × yield × stoichiometric factor — combines design and experimental efficiency | Both |
| E-factor | Mass of all waste per mass of product (includes solvents, excess reagents) | Experimental |
| Space Time Yield (STY) | Product mass per reactor volume per unit time — reactor productivity | Experimental |
| PMI (Process Mass Intensity) | Total mass of all inputs per mass of product; E-factor + 1 | Experimental |
Experiment details
Reactants
Enter all reactants. MW and mass are required to identify the limiting reagent and calculate the theoretical yield. The limiting reagent is marked with ★.
| Compound name | Formula | MW (g/mol) | Mass used (g) | Coeff. | Moles |
|---|
Product & actual yield
Enter the desired product and its MW so the theoretical yield can be calculated. Then enter the actual mass you isolated.
| Product name | Formula | MW (g/mol) | Coeff. | MW × n |
|---|
Results
Reactant mass contributions
Actual vs. theoretical yield
Detailed breakdown & interpretation
| Compound | Role | Formula | MW (g/mol) | Mass (g) | Moles | Coeff. | % of reactants | Visual |
|---|---|---|---|---|---|---|---|---|
| Enter reactants, product, and actual mass above to see breakdown. | ||||||||
Interpretation
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Export
Export your % Yield calculation as a PDF report or CSV data file. PDF opens in a new tab and uses your browser's print function. CSV downloads directly.
Where can I read more?
References are sorted alphabetically by first author.
- ACS Green Chemistry Institute. Green Chemistry Resources & Solvent Selection Guide. acs.org/greenchemistry. — Pharmaceutical Roundtable solvent-selection scoring and PMI benchmarking data.
- P. T. Anastas and J. C. Warner, Green Chemistry: Theory and Practice, Oxford University Press, 1998. ISBN 978-0-19-850698-0. — Original statement of the 12 Principles; Principle 2 frames atom economy alongside yield.
- D. J. C. Constable et al., Green Chem., 2002, 4, 521–527. DOI. — Metrics to 'green' chemistry — which are the best? Compares yield, AE, E-factor, RME.
- R. A. Sheldon, Chem. Ind., 1992, 903–906. — Introduces E-factor; contextualises yield within the wider waste landscape.
- B. M. Trost, Science, 1991, 254, 1471–1477. DOI. — Introduces atom economy; discusses the relationship between yield and selectivity.
Contributors
Roles follow the CRediT taxonomy (Contributor Roles Taxonomy), adapted for educational software. Hover a contributor's name for a summary, or a column header for the definition of that role.
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