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How this works

Your target is your essential monthly spending multiplied by the number of months you want to cover. Essentials are the things you’d still have to pay if your income stopped: rent or mortgage, bills, food and getting to work.

The calculator then counts how long it takes to get there from what you’ve already saved, adding your monthly amount at the end of each month and interest at the AER you enter.

What it assumes

  • Your essential spending stays at today’s level while you build the fund.
  • You save the same amount each month and don’t dip into the pot.
  • Daily amounts use 365 days a year.

Worked example

Six months of £1,800 essentials

  1. Your essentials come to £1,800 a month, so six months is £10,800.
  2. You have £1,000 saved, which covers just over half a month. That leaves £9,800 to go.
  3. Saving £200 a month at 4%, you reach the full target in 3 years 9 months.
  4. Aiming for three months first, £5,400, takes 1 year 9 months, which is a good first milestone.

Worked out with the same maths as the calculator above.

What to do next

Common questions

How many months should I aim for?

Three months is a common starting point. Six makes sense if you’re self-employed, the only earner in your household or your job is less secure. Even one month makes a big difference.

Where should I keep my emergency fund?

Somewhere separate from your current account, easy to reach within a day or two, and paying a decent rate, such as an easy-access savings account or cash ISA.

Should I build an emergency fund or pay off debt first?

Many people do a bit of both: a small buffer first, so surprises don’t go on a card, then focus on expensive debt, then finish the full fund.

What counts as an emergency?

Something unexpected and necessary, such as losing your job, an urgent repair or a vet bill. Planned costs like holidays or Christmas belong in their own savings pots.

Is my emergency fund protected?

Money in UK banks and building societies is covered by the Financial Services Compensation Scheme, up to £120,000 per person, per banking licence, from 1 December 2025.

Sources

Guides on this topic