Mr McEwan, who recently graduated with a Bachelor of Science and Bachelor of Commerce degree, was coy about how much money the app had brought in over the years.
"It's been enough to pay for my tertiary education," he said.
A result was based on an algorithm and a number of factors, he said, but he warned people not to take it seriously.
"It serves as a pretty funny ice-breaker ... We get a lot of people taking it into bars and what they really wanted was to be able to change the scores."
He said he had heard some funny stories, including a man who had received a higher score when he entered his ex-wife's name than that of his current wife.
Mr McEwan admitted his own love life had not lived up to the Love-O-Matic's 91 per cent compatibility scored with his girlfriend. "I made it so that I got a really good score with her - but we broke up a while ago."
The Love-O-Matic app is free to download, but a new feature means that for 99 cents you can buy "love potions" to manipulate the score.
People either loved or hated the application, depending on their scores, he said.
"It's had over 750,000 downloads over the last couple of years and that's been pretty sweet."
In honour of Valentine's Day, any money raised from downloads today will go to the Make-A-Wish children's foundation. '