Use EC50 From Hill when you need to estimate the half-maximal effective concentration by inverting the Hill equation. Enter Concentration, Effect fraction, and Hill slope using the definitions and units below so the result can be reproduced.

Concentration

A finite measured or assumed value.

Effect fraction

A finite measured or assumed value.

Hill slope

A finite measured or assumed value.

The published tool contract uses this rule: Estimate the half-maximal effective concentration by inverting the Hill equation.

EC50 concentration

The calculated ec50 concentration.

The output is an estimate tied to the stated model and coefficients; it is not a direct measurement and should retain that label when reported.

Retain the original Concentration, Effect fraction, and Hill slope values and their units alongside the result. Hill EC50 Fit Check is useful when you instead need to check a Hill-Langmuir fit by predicting the effect fraction at a concentration from the fitted EC50 and hill slope. Hill Number N1 provides another view by helping you convert a natural-log Shannon entropy to the Hill number of order one, the effective number of equally common species, as exp(H).

• Hill EC50 Fit Check

  Check a Hill-Langmuir fit by predicting the effect fraction at a concentration from the fitted EC50 and hill slope.

• Hill Number N1

  Convert a natural-log Shannon entropy to the Hill number of order one, the effective number of equally common species, as exp(H).

• Hill Number N2

  Convert a Simpson concentration to the Hill number of order two as its reciprocal.