Beauty maths

At Vogue, they've worked out the cost per use of some beauty products, making it a little easier to justify your purchases (not that I've ever need help there!) First, a bottle of Butter London nail varnish (£12), works out at 22p per use based on 55 applications.

Bobbi Brown lip colour; you'll get 186 slicks out of this £18 product making the cost per use 10p.

Finally, a Jo Malone diffuser, which at £45 works out at 1p per hour with 3600 hours use.

(via Vogue)