The Reds defender admits the club are relying on the goal threat of striker Luis Suarez too much, although they have won their last two matches through goals from an unlikely source in Daniel Agger and Jordan Henderson.
Brendan Rodgers' side could jump three spots into 10th with a victory at West Ham on Sunday afternoon, although they will be without Uruguayan Suarez for the clash as he is suspended to leave them without a recognised forward.
"If you got points for performances then we'd probably be top of the league. With a killer instinct we'd have 12, 15 more points," Johnson told The Sunday Telegraph.
The 28-year-old England full-back also revealed he is currently studying a maths degree in his spare time, but insists he has not lost his passion for football.
"I was good at maths at school but I didn't really think of anything else but football," he said.
"I'm a firm believer that anyone can do anything if they put their mind to it. If you get the opportunity, take it - more importantly you have to want to take it.
"I love the planning and problem solving, equations, working out, for example, how much fuel a plane needed.
"They have tutorials at the weekend. But, of course, I'm busy at the weekends.
"Don't get me wrong, I love football, I love playing the game, I love playing for Liverpool but sometimes it's good to switch off and be a normal bloke."