You can choose "Imperial" with mile, or "Metric" with km, in the Pacer app. If you would like to change the Unit setting, please kindly find steps below.
For Pacer iOS uses:
Please go to Pacer Home page > tap the profile icon in the top left corner > Settings > "Units" > select "Imperial" or "Metric".
For Pacer android users:
Please go to Pacer Home page > Me > Settings gear in the top right corner > scroll down to "Unit Format" > select "Imperial" or "Metric".