Within the Tinkercad editor, you can click the Bricks icon (at the top right) to see your current design translated into standard sized toy bricks.
Bricks Workspace Icon
The Bricks workspace always represents the current design. A common workflow may be to design in the Tinkercad workspace, then see the Bricks result in the Bricks workspace.
There are 3 design sizes in the Bricks workspace, 1x, 2x, and 3x the current Tinkercad design. Clicking 2x or 3x will double or triple the size of the current Tinkercad design, respectively. Larger sizes may better define the design visually in bricks, as the number of bricks significantly increases for larger designs.
See a complete Instructable on using the Bricks workspace here: