"When I developed it I literally just thought it would be used in my brother's classroom. I didn't think it would be on a scale like this."
At the start of the year Banqer expanded to Australia and now has 100 schools signed up and is running trials in the United Kingdom.
Flutey hopes to expand the app in New Zealand to 60,000 children by June next year after receiving financial backing from Kiwibank.
This year is the second year the bank has funded the app to be used in low-decile schools.
Of the Kiwi schools which use the app 42 per cent are decile 6 or lower.
The app allows students aged 6 to 13 to create an account through a simulated bank where they can earn virtual money and learn about income, expenditure and tax.
They get a weekly salary from their teacher, earn interest, have to pay expenses such as rent on their desk, and can even buy property and insurance.
Flutey said the aim was to give students a taste of the kind of financial decisions adults have to make.
Kiwibank economist Zoe Wallis said improving the financial literacy of children helped them learn how to navigate important money matters in adulthood.
"That's good for them and the New Zealand economy, because boosting kids' financial literacy is a big step toward addressing many of the economic issues we're facing in this country, such as inequality, poverty and lack of opportunity."
Flutey, who runs the company out of Christchurch and has a team of six, said the biggest challenge in launching the start-up was dealing with the unknowns like finding the right team members.
"People will always be the hardest part of business."