The 50/30/20 rule made visible.

Envelope budgeting splits income into three pots: needs, wants, and savings. The classic split is 50/30/20 - 50% to rent, bills, and groceries; 30% to dining out, hobbies, and discretionary spend; 20% to savings and debt repayment. This tool lets you set your own percentages and see the monthly amount in each envelope.

The 50/30/20 split is a starting point, not a rule. High earners often save more than 20%, pushing wants down to 20-25%. People living in expensive cities may need 60% or more for needs, which compresses the other two. The calculator enforces that the three percentages sum to 100% - beyond that, any split is valid.

The approach works because it makes trade-offs visible. If you want to save 30% a month, the wants envelope has to shrink to 20%. If housing eats 55% of income, wants and savings each have 22.5%. The numbers force a conversation the spreadsheet rarely does.

A worked example

Try the defaults: monthly take-home income of 4,000, needs percentage of 50%, wants percentage of 30%, savings percentage of 20%. The tool returns 2,000.00. You can adjust any input and the result updates as you type — no submit button, no reload. That's the real power here: seeing how sensitive the output is to one or two assumptions.

What moves the number most

The result responds to Monthly Take-Home Income, Needs Percentage, Wants Percentage, and Savings Percentage. Not every input has equal weight. Flip one at a time toward extreme values to feel which ones move the needle most for your situation.

The formula behind this

Each envelope equals income multiplied by its percentage divided by 100. The tool validates that percentages sum to 100%. Annual savings is monthly savings × 12. Everything the calculator does is shown in the formula box below, so you can check the math against your own spreadsheet if you want.

Making this stick

The number the tool produces is only useful if you act on it. The simplest habit that works: automate the savings transfer on payday, then spend what's left. Everyone who's told you "pay yourself first" was right; the math here is what makes the first number concrete.

What this doesn't capture

Budgets are snapshots of intent. Real spending includes irregular costs: birthdays, one-off repairs, the occasional bad week. Tracking actual spending for a month before fixing any budget usually reveals 10–20% that didn't make the original plan.