How long of a bike ride is a good workout?

Excuse me, I'm curious about something regarding fitness and cycling. I've heard that bike riding can be an excellent workout, but I'm not quite sure how long I should ride for it to be considered a good workout. Could you please elaborate on that? Is there a specific duration or distance that is generally recommended for a productive and beneficial cycling session? I'm looking to incorporate cycling into my regular exercise routine, and I'd like to make sure I'm doing it right. Thank you for your time.