EC50 Calculator

EC50 Calculator

Calculate EC50 from concentration–response data using four-parameter logistic regression.

⚙️ Calculation Settings

📘 4PL Model

The calculator fits a four-parameter logistic dose-response model:

Y = Bottom + (Top − Bottom) / [1 + (EC50 / X)Hill Slope]

EC50 is the concentration producing 50% of the maximal response between the fitted Bottom and Top values.

📊 Concentration–Response Data

# Concentration Response (%) Action

📈 Results

EC50
Hill Slope
Top
Bottom
50% Response
Data Points
Model
4PL

📉 Dose–Response Curve

The x-axis is displayed on a logarithmic concentration scale. Points represent experimental observations and the curve represents the fitted 4PL model.