Fixed expenses
Fixed costs are the same each month and usually contractual: rent or bond, insurance, loan repayments, subscriptions, school fees. They are predictable, which makes them easy to plan and hard to change quickly.
Variable expenses
Variable costs change with behaviour and circumstance: groceries, fuel, electricity, entertainment, maintenance. They are where day-to-day control lives, and where most overspending happens.
The strategic difference
- Fixed costs are changed once, with effort, and the saving repeats forever.
- Variable costs are changed continuously, with attention, and the saving stops when attention does.
- Most households should review fixed costs annually and monitor variable costs weekly.
Semi-variable costs
Some costs have a fixed base and a variable component — a phone contract with data top-ups, or utilities with a standing charge. Split them into two lines so the controllable part is visible.
A common mistake
Treating a fixed cost as untouchable. Insurance, connectivity and subscriptions are renegotiable far more often than people assume, and one afternoon of calls can outperform a month of careful grocery shopping.