Between the information here :
https://www.media.volvocars.com/glob...specifications
and using this :
https://wahiduddin.net/calc/calc_speed_rpm.htm
is that able to give you the info you need ?
Or as suggested by Soto, if you are just looking to confirm the accuracy of your speedo, a sat nav should give you an accurate reading, or google maps on your phone gives you a speed reading, or any number of apps will give a GPS speed reading. (assuming you have a smart phone of some description)