Percent Recovery Calculator

Percent recovery from recovered and starting mass, or spike recovery for an analytical method.

Percent recovery = (mass recovered ÷ starting mass) × 100. Recovering 4.2 g of pure crystals from 5.0 g of crude solid is 84% recovery. For spike recovery, % recovery = (spiked result − unspiked result) ÷ amount added × 100.

Free, runs in your browser. Nothing you enter is uploaded.

How to use it

Choose mass recovery or spike recovery.
Enter the recovered and starting mass, or the spiked result, unspiked result and amount added.
Read the percent recovery and the mass lost.

What you enter

Recovered mass and starting mass, or spiked, unspiked and added amounts

What you get

Percent recovery
Mass lost

Formula

% recovery = (recovered ÷ starting) × 100 | Spike recovery = (C_spiked − C_unspiked) ÷ C_added × 100

Worked example

Input: 5.0 g crude, 4.2 g dry crystals

Result: 84% recovery, 0.8 g lost

Some product always stays dissolved in the cold solvent, so recrystallization never reaches 100%.

Questions

How do you calculate percent recovery?

Divide the mass you recovered by the mass you started with and multiply by 100. 2.8 g recovered from 3.5 g is 80%.

Is percent recovery the same as percent yield?

No. Percent recovery compares what you got back with what you put in, with no reaction. Percent yield compares product with the theoretical amount a reaction could make.

Why is my percent recovery over 100%?

Usually the product is still wet with solvent or contains impurities. Dry it to constant mass and weigh again.

What is a good spike recovery?

Many validation guidelines accept 80–120% for trace analysis and 98–102% for assays of major components, depending on the concentration level.

Limitations

Mass recovery assumes the recovered solid is dry and pure.

References

AOAC International (2002), Appendix F.

More Chemistry

All free tools · By Dr. Zubair Khalid, DVM, MS, PhD.