Waiting times for Calgary's hospital emergency rooms and urgent care centres are now available online.

The web-based tool, launched Wednesday by Alberta Health Services, is updated every two minutes.

The web page includes a lengthy disclaimer that the times are provided for "general information purposes only" and "patients will be seen in the emergency department based on their medical condition and the severity of their situation."

"Because of the chaotic nature and variability of emergency departments it really is impossible to develop an exact prediction of how long any patient will wait," said health department spokesman Dr. Grant Innes.

Anyone needing emergency care should call 911 or go to the nearest emergency department, the web site says.

Alberta plans to expand the service to other communities in the future, according to a press release.