Emergency Fund Calculator: Target and Time-to-Goal
Your emergency fund has a sweet spot most calculators don't flag. Cross it and HMRC quietly takes a 40% bite of the interest. The number to know before you pick the account.
Emergency fund target by months of cover (£2,000 monthly essentials)
Use monthly essentials (rent, bills, food), not gross income.
Personal Savings Allowance, 2026/27
| Tax band | Annual PSA | Balance at 4.5% to hit it |
|---|---|---|
| Basic rate (20%) | £1,000 | £22,222 |
| Higher rate (40%) | £500 | £11,111 |
| Additional rate (45%) | £0 | £0 |
A 6-month emergency fund of £12,000 already pushes a higher-rate taxpayer over the line. Cash ISA fixes it. Source: gov.uk.
Key takeaways
The emergency fund calculator multiplies your monthly essential expenses by your chosen months of cover (3, 6, 9 or 12) to set the target.
It then models how long it will take to reach the target with monthly contributions and savings interest, returning a date you can plan against.
A Personal Savings Allowance check warns you when expected annual interest crosses the £500 higher-rate allowance, which is the size where a Cash ISA usually beats easy-access savings.
For most UK households a 6-month fund is the sensible default; 3 months only works if you have stable salaried income and a partner with their own buffer.