How to build a budget from your last three months
Start from what you actually spent, not what you hope to spend. Six steps to a budget built on three months of real spending, and how to keep it.
Updated October 31, 2026
Start from what you spent
A budget built on hopes breaks in the first week. One built on what you actually spent holds, because it starts where you already are. Three months is long enough to smooth out an odd week and short enough to be current.
The six steps
1. Gather three months of spending from every account and card.
2. Take out card payments and transfers between your own accounts, so nothing is counted twice.
3. Split fixed bills, like rent, phone and insurance, from everything else.
4. Average each category over the three months. That average is your starting budget. For a bill you pay once a year, divide it by 12.
5. Pick one or two categories to trim, by a small amount. A budget you keep beats a strict one you drop.
6. Check in once a week. Five minutes is enough to see which category is running ahead.
In habitt
habitt builds your first budget from the spending in the accounts you link, leaves out transfers and card payments, and sends an alert when a category is running ahead.
General information to help you think it through, not financial or tax advice.