How big should your emergency fund really be?

A complete method · 11 min read · Free to use, no course required

“Three to six months of expenses” is the most repeated sentence in personal finance and one of the least useful, because it does not tell you which end of the range applies to you, what counts as expenses, or where to keep the money. Here is how to work it out properly.

What the buffer is actually for

It has one job: to absorb a shock without forcing you to borrow at a bad rate or sell something at a bad time. That is all. It is not an investment, so its return does not matter much. It is not a savings goal for a holiday. It is insurance you pay for by accepting a low return on a modest amount of money, and it is the difference between an expensive month and a two-year setback.

Start with the real monthly figure

Not your income. Not your normal spending. Your survival spending: what you would have to pay if income stopped tomorrow and you cancelled everything you could.

• Housing and the utilities that keep it habitable
• Food at home
• Minimum debt payments — missing these has consequences beyond the money
• Transport required to look for or attend work
• Medicines, childcare and any care you cannot pause
• Insurance you must not lapse

For most households this comes to between fifty-five and seventy-five percent of normal spending. Use your figure, not that range.

Then adjust for your actual risk

Now decide how many months. Start at three and move up or down using the following, each worth roughly half a month to a month:

Move up if

• Your income is irregular, seasonal, commission-based or from self-employment
• You are the only earner, or others depend on you
• Your work is specialised and takes a long time to replace
• You have a health condition that could interrupt work
• You own things that break expensively: a house, an older car
• You have little or no access to affordable credit as a backstop
• Your notice period is short or you have no employment protection

Move down if

• You have a stable salaried job in a field with constant demand
• There is a second income in the household
• You have strong statutory sick pay or redundancy protection
• Your fixed costs are low and genuinely reducible at short notice
• You have no dependants and could move somewhere cheaper quickly

A salaried nurse with a working partner and no dependants might land at two and a half months. A self-employed photographer supporting two children might land at eight. Both are correct answers, and neither comes from a slogan.

Build it in three stages, not one

A target of eight months' expenses is paralysing when you have nothing. Break it up:

1. The starter buffer. One round amount — whatever covers a typical unexpected bill where you live. It stops small problems becoming debt. Most people can build this within two months.
2. One month of survival costs. The point at which a delayed payment or a lost client stops being an emergency.
3. The full target. Built slowly, in the background, by automatic transfer. This stage can take a year or more and that is entirely normal.

Where it should live

Three requirements, in this order: you can reach it within a few days, its value does not fall, and it is not so convenient that you spend it by accident. A separate savings account at a different institution from your everyday bank satisfies all three for most people. Anything whose value fluctuates is not a buffer, whatever its expected return.

Write the rules before you need them

The most common way a buffer is lost is not disaster; it is drift. Decide now, in writing, what counts:

• Yes: loss of income, essential repair, medical need, urgent travel for family, an unavoidable bill you cannot otherwise pay
• No: holidays, upgrades, anything that could wait ninety days, opportunities that feel urgent because someone told you they were
• After using it: refilling it becomes the first priority, ahead of extra debt payments and any investing

Buffer or debt first?

The usual sequence is: build the starter buffer first, then clear high-interest debt aggressively, then build the full buffer. The reasoning is simple. Without any buffer, the next unexpected expense goes straight back onto the card you are trying to clear, and you never make progress. But holding eight months in cash while paying high interest on a card is an expensive comfort, so do not overshoot before dealing with the debt.

When it is finished

Stop. A buffer that keeps growing indefinitely is just money doing nothing. Once it reaches the target, redirect the transfer to whatever comes next in your plan, and review the target once a year or whenever your circumstances change — a new dependant, a move, a change from salary to self-employment.

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