How big an emergency fund should be

The reserve in one paragraph

An emergency fund is cash that keeps a surprise from becoming expensive debt. The emergency fund calculator multiplies the essential monthly spending you type by the months of cover you want, then compares that target with what you already hold. It also counts how long the gap takes to fill at the monthly amount you can set aside.

When to use

Use it before a savings goal that can wait. A job loss, a medical bill, or a repair is the kind of shock the reserve is for. It is the wrong tool for a down payment with a date — that is the savings-goal guide — and the wrong tool for a loan payment. That is the affordability guide.

The formula in plain English

Target = monthly essentials × months of cover
Coverage now = current savings / monthly essentials
Gap = target − current savings

Months to the target use the same end-of-month compounding as the savings-goal calculator, so a small return on the cash can shorten the wait. At a zero rate the wait is the gap divided by the monthly contribution. The model does not choose the account, and it does not treat a retirement portfolio as spendable cash.

A worked example

Essentials of 2,000, a 6-month target, 4,000 already saved, and 500 set aside each month at 0%. The target is 12,000. You already cover 2 months. The gap is 8,000. The reserve fills in 16 months. Switch Scenario B to 3 months and the target drops to 6,000.

How to read the result

Three and six months are a teaching range, not a rule. A less stable income often argues for more months. A sturdy cash flow and good insurance can argue for fewer. The coverage figure is months you could pay today. The chart stops in the year the target is reached, or at 30 years if the contribution never gets there.

Common mistakes

Using take-home pay instead of the bills you would still have to pay.

Counting retirement investments as the reserve. Selling them can be slow or costly.

Picking six months because a chart said so, without looking at job stability.

FAQ

Is three months or six months correct?

Neither is universal. Scenario B is there so you can see both sizes with the same spending.

Should the reserve earn a return?

You can type one. Many people keep this money in cash, so a rate near zero is the useful starting point. The page does not pick an account.

What if I already have more than the target?

The gap becomes a surplus and the months remaining are zero. The extra can move to a savings goal. It is not a reason to skip the reserve.

Does inflation shrink the reserve?

Yes, in purchasing power. This page sizes the cash in the currency you type. The inflation calculator shows what idle cash buys later.

Is this financial advice?

No. It is a sizing exercise that runs in your browser.

Related guides

• How a savings goal is calculated — where the monthly amount can go after the reserve is funded.
• Inflation, IPCA, and real return — idle cash and rising prices.
• How much home you can afford — a housing payment is easier to carry beside a funded reserve.

Try it with your figures

Open the emergency fund calculator, set essential spending and the months of cover, then add Scenario B if you want three months beside six. The link keeps the inputs.