SuperDevTools
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Monthly budget calculator

Income
Expenses

Where the money goes

50/30/20 rule

One benchmark among others: a share of income for needs, one for wants, one for savings. Pick a split or type your own.

Split:

A positive difference means above the benchmark, a negative one below. Depending on the city and your situation, needs can go over 50% without the budget being badly run.

How categories are classified

Each category counts as a need, a want or savings. Change it if it doesn't match your situation.

Savings goal

Month-by-month tracking

This is a calculator: the benchmarks shown are only a guide. They don't replace advice suited to your own situation.

The link contains your amounts: only send it to people you trust. The data sits in the address after the # sign and never goes through our server.

Your budgets stay on this device: nothing is sent.

A monthly budget planner that stays on your device

This budget calculator lists your income and expenses, then shows your total spending, what's "Left over", your "Savings rate" and a bar chart of where the money goes. It also works as a 50/30/20 rule calculator, turns a savings goal into a monthly amount and keeps several months side by side. Everything runs in your browser and nothing is sent anywhere.

How to make a budget in 5 steps

  1. Under "Income", enter your "Take-home pay" and any "Other income" such as a side gig or child support. "Add income" gives you another line.
  2. Under "Expenses", fill in the ready-made categories: Housing, Utilities, Transportation, Groceries, Insurance, Subscriptions, Health, Kids, Fun and leisure, Savings, Debt payments and Other. "Add an expense" adds a line in any category.
  3. For a bill you pay once a year, pick "per year" and the tool divides it by 12. A $240 car registration shows "= $20.00 per month".
  4. Read the results and the "Where the money goes" chart.
  5. When the month ends, click "Set up next month (copy)" and only change what moved.

A worked example

Take-home pay is $4,000 a month. Expenses: rent $1,400, utilities $200, groceries $500, transportation $350, insurance $150, subscriptions $60, fun $300 and savings $400. Total expenses, planned savings included, come to $3,360, so $640 is left over.

The savings rate counts planned savings plus any positive leftover: ($400 + $640) ÷ $4,000 = 26%. If part of the $640 ends up spent, the real rate will be lower, which is exactly what month-to-month tracking shows.

Fixed and variable expenses

Fixed expenses come back every month at a known amount: rent or mortgage, insurance, phone plan, loan payments. Variable expenses move around: groceries, gas, eating out, gifts. Pull the fixed ones from your bank statements first, then use the average of two or three months for the variable ones. Yearly costs such as property tax, a warehouse club membership or holiday gifts belong in the budget too: enter them "per year".

The 50/30/20 rule and its limits

The 50/30/20 rule suggests 50% of take-home pay for needs, 30% for wants and 20% for savings and extra debt payments. On $4,000 that means $2,000, $1,200 and $800. In the example, needs (housing, utilities, groceries, transportation, insurance) add up to $2,600, or 65%; wants (subscriptions, fun) to $360, or 9%; and planned savings to $400, or 10%.

Treat it as one benchmark among others, not a grade. In New York, San Francisco or Boston, rent alone can take 40% of pay, and needs then go past 50% without the budget being badly run. The 60/20/20, 70/20/10 and 80/10/10 buttons change the split, you can type your own, and "How categories are classified" lets you move a category, for example a subscription you need for work.

Emergency fund

A cushion of 3 to 6 months of expenses is often quoted for a job loss, a car repair or a medical bill. With $2,960 of monthly expenses outside savings, that is $8,880 to $17,760. It's a rough guide, not a rule. The "Savings goal" block does the math: $6,000 in 24 months takes $250 a month, and with $1,200 "Already saved" it drops to $200 a month.

Spending less without going without

  • Keep only the subscriptions you actually use.
  • Shop around for insurance and phone plans once a year.
  • Plan the week's meals before grocery shopping.
  • Set up an automatic transfer to savings on payday.

Tracking your budget over time

The "Month-by-month tracking" table compares saved months: income, expenses, left over, savings rate and the change in spending from the previous month. "Export CSV" opens the budget in a spreadsheet, and "Print" gives a one-page summary. "Copy shareable link" reopens the month shown; it contains your amounts, so share it with care.

Frequently asked questions

Is my data sent anywhere?

No. Budgets are saved in this browser on this device. The shareable link puts the data after the # sign, a part of the address that browsers don't send to the server.

Should I enter gross or net pay?

Net: the amount that actually lands in your account after taxes and payroll deductions.

How do I handle a bill paid every quarter?

Multiply it by 4 and enter the total "per year". A $75 quarterly water bill becomes $300 a year, or $25 a month.

Can I use pounds or euros?

Yes. The "Currency" menu switches between USD, GBP and EUR; the amounts stay the same, only the symbol and formatting change.