There's an app that will measure your kids' shoe size for free. Yes, really.

Purchasing my son’s first pair of shoes was a memorable milestone event.

He had just learned to walk and we almost cleared out a busy shoe store.

Shoppers found the blood-curling screams hard to bear and left, as the friendly sales assistant tried to manoeuvre a tiny foot onto a cold metal plate.

There was so much crying and kicking that we gave up and pretty much guessed his size.

Now new mums won’t have to do that because a clever Australian businesswoman has invented an app that can “accurately measure” fast growing feet.

Sydney mum Kate Messiter has created KidShoeFit, a free iPad application that provides a quick and easy way to measure kids’ feet.

Parents can place their child's foot on an iPad screen and slide digital rulers to align with the back of the heel and the end of the longest toe.

"Toddlers and little kids change shoe sizes so quickly, it is difficult as a parent to keep up," says founder Messiter.

She is hoping the app will redefine how parents buy kids' shoes.

"KidShoeFit takes accurate foot measurements and automatically generates the three most common size conversions, and it can be used in the comfort of your own home or on the go,"she said.

It's a great idea for online shopping or if you want to spare yourself the struggle of an in-store shoe fitting tantrum.