logo
Products
Technologies
Applications
Services
Resources
Selection Guides
About
BSA Concentration Calculator
Bovine serum albumin (BSA), as its name suggests, is serum albumin obtained from bovine, or cows. It has long found use as a biological protein standard, because it is a well-studied, fairly non-reactive protein of known mass. It is also commonly used as an immunoassay blocker. Samples of cells or tissues are often pre-incubated with BSA to reduce non-specific binding by the antibody of interest.
The concentration of BSA in solution can be determined by substituting the molecular weight, extinction coefficient and λ max into a derived form of the Beer - Lambert Law. A substance's λmax is the wavelength at which it experiences the strongest absorbance. For BSA, this wavelength is 280 nm.
The absorbance at λmax can be measured using a spectrophotometer. There are some important things to keep in mind when measuring 280 absorbance:
  • The BSA should be well-dissolved in solution. BSA precipitation will cause inaccuracies in concentration calculations.
  • The absorbance reading should not exceed the maximum detection limit of the instrumentation. This can be identified by a plateau in the absorbance spectrum. If the absorbance spectrum plateaus, dilute the sample and try again.
  • This calculator assumes a 1 cm pathlength for instrumentation. Standard cuvettes for spectrophotometers are typically 1 cm. If a different pathlength is used, value should be corrected during data entry.
Protein
Absorbance at λmax
Dilution factor (optional)
Pathlength
 cm
Feedback
Have a question or a feature request about this tool? Feel free to reach out to us and let us know! We're always looking for ways to improve!
References
This online resource may be cited as follows
MLA
"Quest Calculate™ BSA Concentration Calculator." AAT Bioquest, Inc., 30 Sep. 2025, https://www.aatbio.com/tools/calculate-BSA-concentration.
APA
AAT Bioquest, Inc. (2025, September 30). Quest Calculate™ BSA Concentration Calculator. AAT Bioquest. https://www.aatbio.com/tools/calculate-BSA-concentration.
BibTeXEndNoteRefMan

  • Select the protein type. Or select "custom sequence" to enter the sequence.
  • Enter the absorbance at λmax. Please use the maximum absorbance as indicated by the spectrophotometric reading (ie. highest peak).
  • If the absorbance is obtained with a diluted sample, enter the dilution factor in order to determine the concentration of the original sample.
  • If pathlength differs from 1 cm, enter corrected value into pathlength textbox.
  • Press calculate to display the concentration.