You can play along with the video in GCEA tuning, if you put your capo on the 2nd fret!
The song charted at number four on the U.S. Billboard Hot 100 when released as a single in 1971 and number six in Canada. The song also spent three weeks at number one on the U.S. Easy Listening chart, and one week at the top of the Canadian AC chart. "If" has been a perennial favorite at weddings ever since it was released and has been covered by many popular artists.