In chrome when you are printing there is an option to change the scale of the printing. This setting can often get modified to change the size of the printing and make either too large or too small.
To locate this scroll down on the left hand side to more settings and click to expand.
It will then look like this.
As you can see there is a scale option make sure this says default not customised. If it says customised change it to default and this should return the size back to default.