There are a few ways you can alter the display features of metric values.

The "Full" option will display the entire number with commas to separate the thousands. The "Formatted" option will round the metric value to the nearest base unit selected.

Users can format Metrics on the Report Builder by selecting the metric of interest.

Metrics can also be formatted by the 'Visualisation' tab, on the right of the report there is a cogwheel. Select 'Visualisations' and then scroll down the metric you would like to format.

Ticking the "Show Split Column" box will reveal the metric split field adjacent to the selected metric field. This displays how much of that metric is attributed to that dimension value from the total - displayed as a percentage.