Most budgets fail because they are based on estimates, not real spending. Your bank statement shows what you actually spent last month, which makes it a much better starting point.
The look-back method
Before setting any budget for next month, look back at your statement for the last three months. Total your spending by category for each month. Now you have your actual average spending per category. Use that as your baseline, not a number you think sounds right.
The 50-30-20 rule applied to your statement
Split your monthly take-home pay into three buckets. 50% for needs: rent, utilities, groceries, loan EMIs. 30% for wants: dining out, shopping, entertainment. 20% for savings and investments. Compare your actual statement categories against these targets. Most people find the wants bucket is the one that overflows.
Automate savings first
Instead of saving what is left after spending, set up an auto-debit on your salary date that moves 20% straight to a separate savings account. This way the savings happen regardless of how the rest of the month goes. Your statement will show this as a consistent debit at the start of each month.
Monthly review ritual
On the last day of each month, download the statement and spend 15 minutes reviewing it. Note which categories went over. Identify the specific transactions that pushed you over. Next month, you will know exactly where the risk is.
Related reading: How to Track Expenses Using Your Bank Statement, How to Reconcile Your Bank Statement, How to Download Statements for All Your Accounts.