Tracey,

To go a bit further, and help you write your calculation line :

1. What is the cell where you store what you call "New sub total for
the day" ?
2. What is the cell where you store what you call "Master total for the
month" ?
Are these inputs always located in a given cell or do they change
location ?

No doubt, you will fix this problem ...

Cheers
Carim