Dose-Response Curve Fitter

Fit dose-response curves using 4-Parameter Logistic regression to calculate IC50, Hill slope, and confidence intervals

4-Parameter Logistic Regression Results

Predicted Values at Key Concentrations

ConcentrationPredicted ResponseObserved ResponseResidual

What is Dose-Response Curve Fitting?

Dose-response curve fitting uses 4-Parameter Logistic (4PL) regression to model the relationship between drug concentration and biological response. It calculates IC50, Hill slope, and other pharmacological parameters essential for drug discovery and toxicology studies.

How to Use This Curve Fitter

Quick guide to get results:

  1. Enter concentration-response data (tab or comma separated)
  2. Results appear automatically with fitted parameters
  3. Download complete analysis or copy specific values

When to Use

This tool is useful when you need to:

  • Calculate IC50 values for drug potency assessment
  • Determine Hill slope for cooperativity analysis
  • Fit dose-response curves in pharmacology studies
  • Analyze toxicity data with EC50 calculations
  • Generate predicted values at specific concentrations

Example Input

Sample concentration-response data:

Concentration Response 0.001 100 0.01 95 0.1 75 1 50 10 25 100 5

Use tab or comma separation between columns.

Example Output

Expected output format:

IC50: 1.23 ± 0.15 Hill Slope: -1.45 ± 0.22 Top: 98.5 ± 2.1 Bottom: 3.2 ± 1.8 R²: 0.998

Includes confidence intervals and goodness of fit.

FAQ

Q: What is the 4PL equation used?
A: Y = Bottom + (Top-Bottom)/(1+(IC50/X)^HillSlope)

Q: How are confidence intervals calculated?
A: Using standard error estimates from the fitting algorithm.