Odds Ratio to NNT Converter

The OR to NNT Converter was created for your own personal use and testing purposes. It is to be used as a guide only. Medical decisions should NOT be based solely on the results of this program. Although this program has been tested thoroughly, the accuracy of the information cannot be guaranteed.

To convert odds ratios to Number Needed to Treat (NNT):

Enter a number that is > 1 or < 1 in the Odds Ratio (OR) textbox.
Enter a number that is not equal to 0 or 1, between 0 and 1 in the Patient's Expected Event Rate (PEER) textbox.

After entering the numbers, click "Calculate" to convert the odds ratio to NNT.

Odds Ratio to NNT Converter

Odds Ratio (OR)
Patient's Expected Event Rate (PEER)¹

Number Needed to Treat (NNT)

Terminology

1. The patient expected event rate (PEER) refers to the rate of events we'd expect in a patient who received no treatment or conventional treatment.

Equations

OR greater than 1:
nnt = (1 - (peer × (1-or))) / ((1-peer) × peer × (1-or))

OR less than 1:
nnt = (1 + (peer × (or-1))) / ((1-peer) × peer × (or-1));