What is a healthy expense ratio?

Under 70 percent gives comfortable room to save. Above 90 percent leaves almost no margin for the unexpected.

Should savings be listed as an expense?

For this comparison, keep savings out of expenses so the surplus shows what is genuinely available to allocate.

What income should I use if mine varies?

Use your lowest recent month, or the average of your three lowest, so the plan holds in a weak month.

Calculator

Income vs Expenses Calculator

Compare everything that comes in with everything that goes out, and see your monthly surplus, deficit and expense ratio.

Income

Salary amount

Side income amount

Expenses

Rent amount

Groceries amount

Transport amount

Debt payments amount

Surplus or deficit

Total income: R 19 500
Total expenses: R 13 900
Remaining: R 5 600
Expenses as % of income: 71.3%

You have money remaining after your planned expenses.

How this calculator works

Add each income source and each expense as its own line. The calculator totals both sides, shows the difference, and expresses expenses as a percentage of income.

That percentage is the useful part. Below 70 percent leaves comfortable room for saving. Between 70 and 90 percent is workable but tight. Above 100 percent means the gap is being filled by savings or credit, which is not sustainable.

The formula

Surplus = Total income − Total expenses. Expense ratio = (Total expenses ÷ Total income) × 100.

Worked example

Income of 18,000 from salary plus 2,400 from freelance work totals 20,400. Expenses of 17,900 leave a surplus of 2,500 and an expense ratio of about 88 percent — workable, but a single unexpected cost would wipe out the margin.

Why this calculation is useful

It is the fastest possible check on financial health. One number tells you whether your current life fits inside your current income, before you get into the detail of individual categories.

Common mistakes to avoid

Using an optimistic income figure from an unusually good month.
Omitting annual costs converted to a monthly equivalent.
Counting a loan drawdown as income.
Forgetting bank charges, subscriptions and small recurring fees.
Reviewing once and never updating as costs increase.