LD50 Calculator

Calculate median lethal dose from toxicity data - the dose causing mortality in 50% of test subjects

Enter Dose-Response Data

Dose (mg/kg)Mortality 1 (%)Mortality 2 (%)Mortality 3 (%)MeanAction
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What is LD50?

LD50 (median lethal dose) is the dose required to kill 50% of a test population. It's a standard measure of acute toxicity used in toxicology to compare and rank the toxicity of substances.

How to Use

  1. Enter doses (mg/kg, usually log scale)
  2. Enter mortality percentages
  3. Add replicates for better accuracy
  4. Click Calculate to fit the curve
  5. View LD50 value and curve fit

Data Requirements

  • At least 4 concentration points
  • Include doses above and below LD50
  • Use log-spaced concentrations
  • Mortality values 0-100%
  • Multiple replicates improve accuracy

Hill Slope Interpretation

  • 1: Standard dose-response
  • < -1: Steep curve (cooperative binding)
  • > -1: Shallow curve (multiple sites)
  • Positive: Inverse agonist or stimulation

Applications

  • Toxicity testing and classification
  • Environmental risk assessment
  • Pesticide safety evaluation
  • Drug safety screening
  • Chemical hazard assessment

FAQ

Q: How is LD50 expressed?
A: Usually in mg/kg body weight, indicating the dose per kilogram of subject weight.

Q: Why use log concentrations?
A: Log scale provides better curve fitting across wide concentration ranges.