Budget calculator

What this calculator does

This budget calculator turns monthly income, recurring expenses, debt payments, and planned savings into a simple cash-flow picture. It is built for a household or personal budget where the question is not just “what do I earn?” but “how much of that income is already assigned, how much is saved, and how much is still unallocated?”. The calculator separates total expenses from planned savings so you can see both pressure on the budget and progress toward goals.

The calculation is global because it does not depend on tax law, banking rules, or official rates. It does not categorize every possible expense; instead it focuses on the categories that usually drive a monthly plan: housing, food, transport, debt payments, other expenses, and savings. Use the output as a planning estimate and update the inputs whenever a bill, salary, or savings target changes.

How to use it

1. Enter monthly take-home income, not annual income.
2. Add housing, groceries, transport, debt payments, and other recurring expenses as monthly amounts.
3. Enter the amount you plan to save or invest this month.
4. Read remaining cash flow first; then review the savings rate and expense ratio to understand why the number changed.
5. Try small changes, such as lowering other expenses or raising savings, to see how sensitive the budget is.

A worked example

If monthly income is 5,000, housing is 1,500, food is 700, transport is 400, debt payments are 300, other expenses are 1,450, and savings are 600, total expenses are 4,350. Assigned income is 4,950 after adding planned savings. That leaves 50 of remaining cash flow, a 12% savings rate, and a 87% expense ratio. The useful insight is not only that 50 remains; it is that most of the income has a clear purpose already.

What the result means

A positive remaining cash flow means the plan fits inside the income before irregular costs. A negative result means the plan assigns more money than comes in, so something must change: income, spending, savings, or timing. A high savings rate is good only if the remaining cash is still realistic. A low expense ratio leaves room for emergencies, while a high ratio may make the budget fragile.

Common mistakes

• Entering gross salary instead of take-home income after tax and payroll deductions.
• Forgetting irregular but predictable costs such as annual insurance, car service, school fees, gifts, or subscriptions.
• Counting savings twice: once as a saving target and again inside another expense category.
• Treating a positive remaining amount as free spending even though upcoming irregular bills may still need a reserve.

When it is useful

Use it when setting a first monthly budget, checking whether a rent or loan payment is affordable, deciding how much to save, or reviewing why money feels tight even when income looks adequate.