Percent Recovery Calculator
Written by the percentages.co.uk team. Reviewed for accuracy.
This calculator works out the percent recovery for a chemistry experiment or laboratory procedure. Enter the initial and recovered amounts in your chosen unit (grams, moles, millilitres and more) to see your recovery percentage, amount lost and a quality assessment of your result.
How it works
Percent recovery measures how much of a substance was successfully retrieved after a purification, extraction or synthesis procedure, compared to the theoretical amount you started with. A 100% recovery would mean no substance was lost; in practice, some loss is almost always expected.
The formula
% Recovery = (Recovered amount / Initial amount) × 100
Amount lost = Initial amount - Recovered amount
Quality benchmarks
- 90% and above: Excellent recovery
- 80-89%: Good recovery
- 70-79%: Acceptable
- Below 70%: Poor; review your procedure for sources of loss
Why this works: Expressing recovery as a percentage of the initial amount gives a standardised measure that is comparable across experiments of different scales.
Worked examples
A student starts a recrystallisation with 5.00 g of impure compound and recovers 4.25 g of purified product. What is the percent recovery?
- % Recovery: (4.25 / 5.00) × 100 = 85%
- Lost: 5.00 - 4.25 = 0.75 g
Answer: 85% recovery (Good)
A pharmaceutical synthesis targets 10 mmol of product but yields only 6.2 mmol after workup. What is the percent recovery?
- % Recovery: (6.2 / 10) × 100 = 62%
- Lost: 3.8 mmol
Answer: 62% recovery (Poor; review procedure)
A liquid extraction begins with 50 mL of solution and recovers 48.5 mL. What is the recovery?
- % Recovery: (48.5 / 50) × 100 = 97%
- Lost: 1.5 mL
Answer: 97% recovery (Excellent)
An A-level student expects 2.50 g of aspirin from a synthesis experiment but only obtains 1.93 g. What is the percent recovery?
- % Recovery: (1.93 / 2.50) × 100 = 77.2%
Answer: 77.2% recovery (Acceptable)
A food science technician recovers 840 g of extract from 1,000 g of raw material. What is the percent recovery?
- % Recovery: (840 / 1000) × 100 = 84%
- Lost: 160 g
Answer: 84% recovery (Good)
When to use this
- A-level and university chemistry: A common calculation in A-level chemistry practicals and university lab reports where students must assess the efficiency of a synthesis or purification.
- Pharmaceutical manufacturing: Tracking yield throughout multi-step drug synthesis to identify steps where product is being lost unexpectedly.
- Environmental analysis: Measuring how much of a contaminant is recovered when extracting samples from soil or water, used to validate analytical methods.
- Food and ingredient processing: Calculating extraction efficiency when isolating compounds such as proteins, oils or pigments from raw food materials.
Understanding the result
A result above 100% indicates a contaminated product (impurities have been weighed as part of the recovered mass), a calculation error or a systematic error in the procedure. This should be investigated rather than reported as a positive result.
Low percent recovery is usually caused by product left in apparatus, incomplete transfer between vessels, product dissolving in wash solvents, or incomplete precipitation during crystallisation. High losses at a specific step should prompt technique review.
Related concepts
➡ Percent recovery is closely related to percentage yield, which also expresses actual output as a fraction of the theoretical maximum. See the percentage change calculator to express any two-value comparison as a percentage. ➡ For calculating mole percentages in a mixture, use the mole percentage calculator to find each component's share of total moles. ➡ To find the mass percentage of a solute in a solution, the mass percent calculator expresses solute mass as a percentage of total solution mass.
How to do this in Excel
=(B1/A1)*100
Put initial amount in A1 and recovered amount in B1. For amount lost: =A1-B1.
How to do this without a calculator
Divide recovered by initial, then multiply by 100. For a quick estimate: if you started with 5 g and recovered about 4 g, that is 80%. If you recovered about 4.5 g from 5 g, that is 90%.
Common mistakes
Confusing percent recovery with percent yield
Percent yield is calculated from the theoretical yield based on stoichiometry and is used for reactions. Percent recovery is used for purification procedures where no chemical reaction occurs (recrystallisation, extraction, filtration).
Not accounting for residual solvent in the recovered mass
If the product has not been fully dried before weighing, residual solvent will inflate the recovered mass and overstate the percent recovery. Always dry thoroughly and record mass after drying.
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