YNAB

YNAB, short for You Need A Budget, is a budgeting app built on one rule: give every dollar you have right now a job. When money arrives, you assign it to categories such as rent, groceries, car repairs or a holiday fund until nothing is left unassigned. When you overspend in one category, you move money from another, so the plan always matches the cash you hold.

It runs on the web and on phones, and it can import transactions from linked bank accounts or take them entered by hand. Many people pick it because it plans with money already in the account rather than with next month's income. It has a free trial and then a paid subscription, with no free plan. Expect a learning period; the method takes a few weeks to feel natural, and the company publishes guides and classes for that.