Every day, J-Spending calculates your expected account balance.
This is highly dependent on which bills have already cleared your account.
Referencing this image, if your Aug 27th paycheck has already been deposited to your account, then we should expect that your account has more money.
However, if your Netflix payment went through early, then we would expect your account would have less money.
You can manually select a bill (or income) in this list and check it off if it has already been posted to your account, or un-check it if it has not been posted.
In the Premium Package, J-Spending will monitor your bank account for you and try to match your expected bills to your actual account transactions!