LD50 Calculator

The LD50 Calculator estimates the median lethal dose based on population size, dosage, and mortality count. This tool helps toxicologists and safety professionals determine the acute toxicity of substances. Whether you are analyzing chemical hazards for regulatory compliance or conducting lab screenings, this calculator provides accurate GHS classification estimates to ensure safety standards are met.

Population Size Total number of test subjects in the experiment

Dose (mg/kg) Amount of substance administered per body weight

Mortality Count Number of subjects that died at this dose

Test Species

Confidence Level: 95%

Use Probit Analysis

Quick Examples:

How Median Lethal Dose Is Calculated

The Median Lethal Dose (LD50) represents the specific amount of a substance needed to kill 50% of a test population. This calculator uses linear interpolation to estimate this value by scaling your experimental dose data to the 50% mortality threshold.

LD50 = Dose × (50 / Mortality %)

Where:

Dose = Amount of substance administered (mg/kg)
Mortality % = Percentage of the test population that died

First, the tool converts the raw mortality count into a percentage based on your total population size. Next, it applies the interpolation formula to find the exact dose corresponding to 50% death. This process normalizes the data, allowing for accurate comparison between different substances. Finally, confidence intervals are calculated to determine the statistical reliability of your result.

What Your Median Lethal Dose Means

Understanding your LD50 value helps classify chemicals by their acute toxicity level according to GHS standards. A lower number indicates a more dangerous substance, often requiring stricter safety measures.

Highly Toxic (Category 1)

If the result is less than 5 mg/kg, the substance is extremely dangerous. This demands "Danger" labels, skull and crossbones symbols, and maximum containment protocols to prevent fatal exposure.

Moderately Toxic (Category 3)

Results between 50 and 300 mg/kg indicate the substance is harmful if swallowed. This usually requires "Warning" labels and the use of protective gear during handling.

Practically Non-Toxic (Category 5)

Values above 2000 mg/kg suggest low acute risk, similar to table salt. While safer, standard precautions should still be maintained to avoid accidental ingestion.

Pro Tip

Compare your calculated results with established Safety Data Sheets (SDS) to validate your experimental accuracy.

Important Note: Always remember that species differences significantly impact these results, so avoid applying animal data directly to humans without clinical validation.

This tool is for informational and educational purposes only and is not a substitute for professional toxicological assessments. Always consult a qualified toxicologist or regulatory safety officer for official hazard classification.