NIOSH logo and tagline

Skin Permeation Calculator

woman smelling flowers, latex gloves, chef cooking over hot grill

The skin permeation coefficient (kp) is a measure of the conductance of skin to a particular chemical from a particular vehicle. This calculator estimates the value of kp from an aqueous vehicle using three different models: Frasch, Potts & Guy and Modified Robinson.

Two inputs are required: molecular weight (MW) and the base-10 logarithm of the octanol-water partition coefficient (logKow) of the compound of interest. These models have been optimized based on experimental data compiled by Flynn.

The user may also browse the Flynn data base of experimental kp‘s. Calculation of the modeled kp will automatically be performed for the chosen chemical.

A downloadable version of the Skin Permeation Calculator is now available. Please click here to download an executable file to your computer.

Clicking on the .jar file will open the calculator on your computer.

For additional information, contact Ray Wells (


  • Frasch Model
    Frasch, H. F. (2002) A random walk model of skin permeation. Risk Anal. 22, 265-276
  • Potts and Guy Model
    Potts, R. O., and Guy, R. H. (1992) Predicting skin permeability. Pharm. Res. 9, 663-669
  • Modified Robinson Model
    Wilschut, A., ten Berge, W. F., Robinson, P. J., McKone, T. E. (1995) Estimating skin permeation. The Validation of five mathematical skin permeation models. Chemosphere 30, 1275-1296
  • Flynn Data Base Flynn, G. L. (1990) Physicochemical determinants of skin absorption. IN: Garrity, TR, Henry, CJ (Eds) Principles of route-to route extrapolation for risk assessment. Elsevier, New York, pp 93-127.