Your most common 3 scales in the world of model car collecting are 1:18, 1:43 and 1:64.
These scales refers to how many times smaller the model is to the vehicle in real life - the larger the number the smaller the model.
For more information about Understanding Scales here
Diecast Car Scales:
1/12 scale - approximately 34cm long
1/18 scale - approximately 25cm long
1/24 scale - approximately 19cm long
1/32 scale - approximately 15cm long
1/43 scale - approximately 10cm long
1/64 scale - approximately 7cm long
