Documents that add themselves up
Bill is an invoice that computes subtotal, discount, tax and due date, prints on one page, and — in Pro — keeps a register of every invoice with outstanding amounts, days overdue, status and aging buckets. Principal is a loan schedule of up to 480 payments that stops itself at exactly zero, with extra payments, payoff date and interest saved in Pro.
Books and debts
Ledger is the bookkeeping side: a transaction log where the category carries the sign, so amounts stay positive and every total is a plain SUMIFS — year totals free, monthly, quarters and a P&L by category in Pro. Settle is the other side of borrowing: list the debts, pick snowball or avalanche, and Pro runs the payoff month by month with the extra rolling from each cleared debt to the next.
Rounded like a bank
Both round where money is rounded: discount and tax to cents on the invoice, interest to cents each month on the loan, with the last payment absorbing the odd cents. The Formulas sheets show where.
What the free version includes
The main sheet, with a credit line kept. Pro adds the register, the lists that feed the dropdowns, extra payments, the comparison grid, the month-by-month schedules and the formulas walkthrough.