The toothbrush hack every parent should know about.

Sometimes a simple hack comes along and totally blows your mind – this is one of them.

Toothbrushes – we all (hopefully) use them, but it turns out we’ve been doing it wrong.

A British mum named Holly Benn has enlightened us with a few home truths about the humble toothbrush.

According to Holly, the coloured parts on your kids’ toothbrush bristles are actually an indicator of where you should apply the toothpaste and how much you should use.

Sharing the hack on a community Facebook page, Holly seemed as surprised as the rest of us by this new discovery, which definitely makes us feel less alone in the world of dental hygiene.

“Tell me I am NOT the only one who didn’t know that the coloured bristles on children’s toothbrushes are ‘toothpaste indicators’ that tell you where to put it and how much toothpaste to use!?” she wrote.

And like the rest of us, it turns out Holly has been doing it all wrong, too.

“I have totes been using too much!!” she added.

Well, that explains why we’re constantly running out of toothpaste, too.

Holly’s post has been shared almost 5000 times, and judging by the comments, everybody is as shook as we are by this newfound pearl of wisdom.

“I Thought It Was To Make Them Look Pretty,” wrote one person, capitalising every word, because that’s how huge this is.

“Interesting! Learn something new every day,” commented another.

Seriously, who knew.