The QP à Équation is a luxury wristwatch by Greubel Forsey.

This model features a bidirectional perpetual calendar (day, date, month, calendar year, leap year, day/night) and an equation of time with month, season, solstice and equinox.

It has a red gold case and a chocolate-coloured dial. The hand-wound movement is equipped with a Tourbillon 24 Secondes and has 4 patents.

The watch was launched in 2014 with white gold case and anthracite dial in a 5-pieces-edition, followed by a variant with rhodium-coloured gold dial in 2017. In the same year the watch won the Calendar Watch Prize at the Grand Prix d'Horlogerie de Genève. A variant with red gold case was presented in 2020.