"Three to six months of expenses" is the most repeated line in personal finance, and most people quietly round it down to three. That's a reasonable first target. It isn't a finish line.
An emergency fund has one job: to keep a bad month from turning into new debt. So the right size depends on which bad months you're exposed to, not on a rule that was written for everyone.
Start with the right number
Size the fund on what you spend, not what you earn. Add up the bills that don't stop if your income does: housing, utilities, groceries, insurance, transportation and minimum debt payments. Leave out the things you'd cut in a crisis. That figure, sometimes called a bare-bones budget, is usually well below your take-home pay, which makes the target less daunting.
Then ask how long a bad stretch would last
Three months covers most one-off shocks: a car repair, a medical bill, a gap between jobs in a field that's hiring. Lean toward six months, or more, if any of these are true:
- Your household runs on a single income.
- Your pay is irregular, commission-based or seasonal.
- Job searches in your field tend to run long, or you're senior enough that the right role takes time to find.
- You own a home, or have dependents or health needs that make costs less predictable.
Build it in the right order
If you're starting from zero, a smaller first step helps. A cushion equal to your highest insurance deductible keeps a single bad week from landing on a credit card. After that, most frameworks put capturing any employer retirement match and paying down high-interest debt ahead of growing the fund past three months, because card interest compounds against you faster than savings compound for you.
Keep it boring and close
Keep the fund in a separate, federally insured savings account, ideally a high-yield one, at a bank you don't use for everyday spending. You want it to earn something, be reachable in a day or two, and be just inconvenient enough that it doesn't become the vacation fund.
Then automate it. A fixed transfer on payday, even a small one, does more than a big intention. When you do use the fund, that's it working. Rebuild it the same way, one payday at a time.