Free-standing ashtrays are available in various heights, making them suitable for a wide range of scenarios. If you have an area which has seats, you should aim for an ashtray which is around 70-80cm high. This should be short enough for people sitting down to reach easily, but high enough to create a balance for those who may be standing up.
For areas where you know most people will be standing up when using the free-standing ashtray, opt for a height of around 120cm. This will allow most people to use the ashtray comfortably while smoking.