Entry is €6 which you can pay by tapping your card on the reader by the gate. The climb up a narrow spiral staircase is steep, but it is broken into sections due to exhibits on different floors. The film (which has English and German subtitles) is interesting about the history of Groningen. I was lucky as there were not many climbers, it looked like there were a limit of 30 at any one time which is good as it could get tricky to pass others. The view from the top is lovely of the city - although obviously you are standing in one of the main landmarks! A free alternative is to visit the viewing platform on the top floor of the nearby Forum Groningen, not as high but you can of course see the Martinitower.

I paid EUR6 by credit card at the automatic gate at the bottom, then I climbed up to the first viewing platform at about 30m, then went up again to the level behind the clock faces. Good view of the flat countryside all around and enough space to sit or stand. This high up it can be windy, even if it is calm at ground level. It takes some time to get up and down, because you have to wait for people coming the other way. There is some information on several levels about the tower and bells in Dutch, English and German. Worthwhile if you have time.

To get a good overview of the city of Groningen, the view from the Martini Tower is fantastic. This climb consists of almost 300 steps. There are several floors with the necessary information. Passing visitors on the stairs sometimes requires some patience.