What this calculator works out
Your survival budget is the smallest amount of money you need each month to keep going. Housing, council tax, energy, food, getting to work, insurance you cannot drop, care costs and the minimum payments on any debts. Nothing else. No streaming, no eating out, no holidays, no new clothes. It is not how you want to live — it is the floor you would drop to if things got tight.
Almost nobody has worked this number out, and it is one of the most useful figures in a person's financial life, because three other things hang off it: how big your emergency fund needs to be, what you would need to cover if your income stopped, and how much real headroom you have each month once the essentials are paid.
The method, in full
There is no cleverness here, and that is deliberate — you should be able to check every step:
- Add up the ten essential categories. That total is your survival number.
- Multiply it by twelve for the annual figure.
- Take the survival number off your monthly take-home pay. What is left is your headroom — the money that decides whether you get ahead or tread water.
- Divide the cash you could reach today by the survival number. That is how many months you could survive if your income stopped tomorrow.
- Multiply the survival number by three and by six for the two buffer targets most people are told to aim at.
Why it is your survival spending, not your full spending
Emergency fund advice usually says ‘three to six months of expenses’, and people quite reasonably read that as three to six months of everything they currently spend. That produces a frightening, distant number that stops a lot of people even starting. In a genuine emergency you would cut back to essentials anyway — so the essentials are what the buffer needs to cover. The target gets smaller and the job gets doable.
The assumptions, stated plainly
- Everything is monthly. If a bill is annual — car insurance, a TV licence — divide it by twelve before you enter it. Annual bills are the most commonly missed items in a budget.
- Debt means minimums only. Put in the contractual minimum payment, not what you are currently overpaying. Overpayments are a choice; minimums are not.
- No inflation, no interest, no growth. This is a snapshot of the month you are in, not a forecast. It is deliberately simple so it is checkable.
- Nothing is rounded up behind your back. The result is your figures added together. Where a figure is shown to the nearest pound it is only the display that is rounded — the arithmetic runs on what you typed.
- Your figures stay in your browser. There is no server call. Close the tab and they are gone, so print or copy the result if you want to keep it.
Being honest about the numbers you enter
The commonest error is optimism. People enter what they think they spend on food rather than what the bank statement says, and the survival number comes out low enough to be useless. Twenty minutes with three months of statements beats an hour of guessing. If you would rather work through it in a structured tool first, the MoneyHelper budget planner is free, government-backed and thorough.
The second commonest error is the opposite: treating things as essential that are not. The gym is not survival. The phone contract probably is, at some level, but the handset upgrade is not. Be strict. The point of the number is to know your genuine floor, and a floor with a Netflix subscription in it is not a floor.
What to do with the answer
Write it down somewhere you will find it. The day you need your survival number — redundancy, a drop in hours, a partner's income stopping — is precisely the day you will not feel like doing sums. Then use it twice: to size your emergency fund with the emergency fund calculator, and to see what your headroom could do against expensive debt with the debt payoff calculator.
Most money stress is not really about not having enough. It is about not knowing. A survival number replaces a fear you cannot measure with a figure you can, and that on its own makes money a great deal less frightening. If you would like someone to work through yours with you, the free Financial Freedom Score takes about seven minutes, and the £39 Financial Health Check (free for Buzz Accounting clients) goes through it properly with a coach.