How to increase/decrease the size of Raised button

Raised buttons have a minimum size of 88.0 by 36.0

To increase/decrease the size of raised button , wrap the raised button in a container or in sized box and give them the desired height and width.

For Example->

SizedBox(
width: 100, // specific value
height: 40.0, // specific value
child: RaisedButton(
onPressed: () {},
child: Text("Hello Everyone"),
),
),

or

Container(
width: 100,
height: 40.0,
child: RaisedButton(
onPressed: () {},
child: Text("Hello Everyone"),
),
),

Now the Raised Button will have width as 100 and height as 40.

Another better Option is to use ButtonTheme

ButtonTheme(
minWidth: 100.0,
height: 100.0,
child: RaisedButton(
onPressed: () {},
child: Text("Hello Everyone"),
),
);