Number of beats in 15 seconds = now multiply this number by 4 to tell how many times your heart beats in one minute. number of beats in 15 seconds x 4 = beats per minute. now multiply this times 60 to tell how many times your heart beats in one hour. number of beats in 1 minute = x 60 = beats per hour. now multiply this times 24 to tell how many times your heart beats in one day. number of beats in 1 hour = x 24 = beats per day.