Huda Beauty's secret to perfect brows is a blast from the past

Drag out your old pencil case

Who would've ever thought beauty and mathematics would go hand in hand? But then again, who would've thought you could take off make-up with shaving cream? But in a world where new beauty hacks are constantly streaming through our social feeds, anything goes. Including Huda Kattan's choice of eyebrow shaping tool.

In one of her latest beauty tutorials on Instagram, the famous beauty blogger revealed her secret to symmetrical eyebrows - a caliper.

For those of you who don't remember what this is, it's that weirdly heavy metal ruler that's used to measure both external and internal distances. Naturally, this makes it a cracker of a tool when it comes to measuring the symmetry of your brows. A secret Huda has been sitting on for years. But now, we can all do as she does. And, once you've got your brows in order – find your perfect mascara to finish off your eyes – this quiz matches you with *the* best ones for you.

First, Huda makes sure her eyebrow line is even. Then, she uses the ends of the caliper to work out the width of her nose and how wide the gap between her brows should be for the most flattering shape. She even uses it to help create the perfect arch and length.

So next time you shade in your brows, unearth your old mathematics pencil case and drag out your caliper.