It's 3000 for the whole day.  I have a heart rate monitor that allows you to put in some pretty specific data to more accurately count calories burnt. When I was training for a 10K race last year, I found I was burning roughly 100 calories per km (160 cal per mile). That's running, though, I don't think for walking it'd be as much - due to my fit privilege, my heart rate stays well under 100 even when I'm walking very briskly.