US Emergency fund calculator

How big should an emergency fund be?

An emergency fund is accessible cash set aside to cover essential costs if your income stops or an unexpected bill lands — job loss, illness, a car or boiler repair. The standard guidance is 3 to 6 months of essential expenses:

Target fund = essential monthly expenses × months of cover

• 3 months — a minimum buffer; reasonable for dual-income households with very stable jobs.
• 6 months — the common standard for most people.
• 9–12 months — sensible if you're self-employed, on variable income, the sole earner, or in a sector where finding a new role takes longer.

Count essential expenses, not your whole budget

Base the target on what you'd actually have to spend in a crisis: housing (rent or mortgage), food, utilities, transport, insurance, and minimum debt repayments. Leave out discretionary spending like dining out, subscriptions, and holidays — in an emergency you'd cut those, so funding them would oversize the target.

Worked example

Essential expenses 2,500/month, target 6 months, 3,000 already saved, saving 300/month:

• Target fund: 2,500 × 6 = 15,000
• You currently have 1.2 months of cover (3,000 ÷ 2,500).
• Shortfall: 12,000 → at 300/month, about 40 months to fully fund.

If that timeline feels long, even reaching one month of cover first dramatically reduces the chance that a small shock turns into expensive debt.

Where to keep it

An emergency fund's job is to be safe and accessible, not to earn the highest return. Keep it in an instant-access or high-yield savings account — separate from your everyday current account so you're not tempted to spend it, but reachable within a day or two. Avoid tying it up in investments that can fall in value exactly when you might need the money.

Building it without straining

• Automate a transfer on payday so it happens before you can spend.
• Start small. A first milestone of one month's expenses is more motivating than staring at the full target.
• Funnel windfalls in — tax refunds, bonuses, gifts — to accelerate progress.
• Top it back up after you dip into it; an emergency fund is a revolving buffer, not a one-time goal.

What this calculator doesn't cover

• Interest earned on the fund (kept simple — emergency cash earns little)
• Inflation adjusting your expenses over time
• Irregular or one-off contributions
• Whether to prioritise the fund over high-interest debt (often a personal balance of both)

A common order of priority: build a small starter buffer (around one month), clear high-interest debt, then grow the fund to your full 3–6 month target.