Sigmoid Emax (Hill) Effect and Its Inverse
Sigmoid Emax (Hill) model: the effect at a concentration, or the concentration that gives a target effect, from E0, Emax, EC50 and the Hill coefficient.
Open the calculator → Runs in your browser. Data leaves only if you deliberately send a problem report from the interactive tool.
Example
- Baseline effect E0
- 0
- Emax
- 100
- EC50
- 10
- Hill coefficient n
- 2
- Concentration
- 20
Result: Effect 80 at concentration 20.
The tool opens with these values already filled in. Replace them with your own.
What you enter
- Baseline effect E0
- Emax (negative if inhibitory)
- EC50
- Hill coefficient n
- Concentration
- Target effect
How this is calculated
Citation
Stated arithmetic: the sigmoid Emax model, E = E0 + Emax C^n / (EC50^n + C^n), named for A. V. Hill, and its inverse for the concentration that gives a target effect. Every parameter is the reader's.
A reference and educational tool. Not medical, legal, or financial advice, and not a substitute for clinician judgment.