Likelihood Ratio Calculator [Odds, Probability, Ratio]
To find the Positive Likelihood Ratio, divide sensitivity by (100 minus specificity). For the Negative Likelihood Ratio, divide (100 minus sensitivity) by specificity.
Formula:
Positive LR = SE ÷ (100 – SP)
Negative LR = (100 – SE) ÷ SP
Table of Variables
| Variable | Meaning |
|---|---|
| SE | Sensitivity (%) |
| SP | Specificity (%) |
| LR | Likelihood Ratio |
What is a Likelihood Ratio Calculator | Predict if a patient’s diagnostic test is likely to be positive or negative:
Imagine a doctor running tests to find out if a patient has a disease. The test comes back positive — but what does that actually mean? That’s where the Likelihood Ratio Calculator comes in. It helps you understand how much a test result changes the chance that someone really has (or doesn’t have) a condition.
This tool is super useful in medicine and forensics. Using values like sensitivity and specificity, it gives you two numbers: a positive likelihood ratio (how likely a positive result means you really have the condition) and a negative likelihood ratio (how likely a negative result rules it out). It’s often used alongside tools like the likelihood ratio nomogram or a pretest probability calculator to get the full picture.
Whether you’re working with a forensic test, a DNA match, or trying to understand medical results better, this calculator makes tough statistics easy. So next time you’re staring at terms like odds likelihood ratio, post-test probability, or log likelihood ratio, just plug in the numbers — and let this calculator do the thinking.
