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Emergency Fund Calculator

Work out how big your emergency fund should be from your essential monthly expenses, then how many months of saving it takes to get there.

Emergency Fund Calculator: with the default inputs, target emergency fund is $22,800.

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Try an example
Target emergency fund
$22,800
Still to save
$14,800
Months until funded
23
In words
About 1 year, 11 months at $600 a month.
Months you can cover today
2.1
Amount above target
$0
Interest earned while saving
$1,000
Assumptions
  • Contributions arrive at the end of each month and the balance compounds monthly at a rate derived from the APY.
  • Essential expenses are constant — no inflation adjustment over the saving period.
  • The target is a multiple of essential expenses only; income and household size affect it only through what you enter.
How much runway your cash actually buys
$0$20k$40k$60k1,9002,8503,8004,7505,700Under 1 month1–3 months3–6 months6–12 monthsOver a yearYou · 2.1 monthsEssential monthly expensesCash on handHow much runway your cash actually buys
Balance while you save
$0$10k$20k04812162023Month
BalanceTarget
What each level of runway costs
Months of runwayFund sizeStill to saveMonths to get there
1$3,800$0already there
3$11,400$3,4006 months
6$22,800$14,8001 year, 11 months
9$34,200$26,2003 years, 4 months
12$45,600$37,6004 years, 7 months

Same expenses and contribution, different targets.

Math verified by automated testsUpdated 2026-09-092 sources cited

How this is worked out

The formula

Target fund = essential monthly expenses × months of runway
Shortfall = max(0, target − current savings)
Monthly rate r = (1 + APY)^(1/12) − 1
Months to fund n = ln((target·r + contribution) ÷ (current·r + contribution)) ÷ ln(1 + r)
  (with r = 0 this collapses to shortfall ÷ contribution)

Open How it’s calculated above to see this worked through with your own numbers.

What you enter

Essential monthly expenses
Rent or mortgage, utilities, groceries, insurance, minimum debt payments, childcare. Not holidays or restaurants.in dollars · 0 or more · defaults to 3800
Months of runway you want
Three months is the usual floor, six the common target, twelve for volatile income.from 0 to 36 · whole numbers only · defaults to 6
Emergency savings today
Only money you could spend this week — not retirement accounts.in dollars · 0 or more · defaults to 8000
Monthly contribution
What you can add each month until the fund is full.in dollars · 0 or more · defaults to 600
Savings APY(under More options)
High-yield savings and money-market accounts have paid roughly 4% recently; a checking account pays nothing.a percentage · from 0 to 20 · defaults to 4

What you get back

Target emergency fundmain answer
Still to save
Zero once you're fully funded.
Months until funded
Rounded up to a whole month, including interest earned along the way.
In words
Months you can cover today
Current savings ÷ essential monthly expenses.
Amount above target
Cash beyond the target, which usually belongs somewhere higher-yielding.
Interest earned while saving

What this assumes

  • Contributions arrive at the end of each month and the balance compounds monthly at a rate derived from the APY.
  • Essential expenses are constant — no inflation adjustment over the saving period.
  • The target is a multiple of essential expenses only; income and household size affect it only through what you enter.

About this calculator

An emergency fund is boring, low-yielding cash whose entire job is to keep a bad month from becoming a bad decade. It is the difference between a broken transmission being an annoyance and being a payday loan. This calculator sizes the fund from your own essential spending and then tells you how long it takes to fill.

Sizing it: three months, six, or more

The standard advice is three to six months of essential expenses, and the spread between those two numbers is really a question about how quickly you could replace your income.

  • Three months suits a dual-income household in a field that hires quickly, with no dependants and stable health costs. One earner losing work still leaves money coming in.
  • Six months is the sensible default for a single earner, a household with children, or anyone whose job search would realistically run a full quarter.
  • Nine to twelve months is for commission or freelance income, a one-earner household, a specialised role with few local employers, a business owner, or anyone within a few years of retirement, where selling investments in a downturn does lasting damage.

Note what goes in the expense figure: rent or mortgage, utilities, groceries, insurance, transport, childcare and minimum debt payments. Not holidays, not restaurants, not subscriptions you would cancel in week one. Emergency budgets are smaller than everyday budgets, and using your full spending inflates the target by a third or more.

Reading the results

Months you can cover today is the number to watch while you build. Going from zero to one month removes most of the risk of a payday loan; the later months buy time rather than survival. Months until funded includes interest, which matters less than people hope — at 4% APY on a partly-built fund, interest usually covers under a tenth of the goal.

Where to keep it

Somewhere boring, separate and same-day accessible: a high-yield savings account or a money-market fund, not the checking account it will leak out of, and not investments that can be down 20% exactly when you need them. The order of operations most planners use is one month of expenses first, then any employer 401(k) match, then high-interest debt, then the rest of the fund.

When to hold more, or less

Hold more if your income is lumpy, your household has one earner, your health costs are unpredictable, or you own a home with deferred maintenance waiting. Hold less if you have a genuinely reliable backstop — a large taxable brokerage account, a partner's stable income — but be honest about whether you would actually use it.

Frequently asked questions

How much should I have in an emergency fund?

Three to six months of essential expenses for most people, and nine to twelve if your income is variable or you are the only earner. Use essential spending, not total spending — the difference is often 30%.

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

Build one month of expenses first so a surprise does not go straight onto a credit card, then attack debt above roughly 8% interest, then finish the fund. Always take a full employer 401(k) match ahead of both.

Where should I keep my emergency fund?

A high-yield savings account or money-market fund at a separate bank: FDIC or SIPC covered, same-day access, no market risk. Certificates of deposit and investments fail the access test exactly when you need them.

Does an emergency fund include my retirement account?

No. Early withdrawals from a 401(k) or traditional IRA cost income tax plus a 10% penalty, and selling in a downturn locks in losses. Count only money you can spend this week.

What counts as an emergency?

Job loss, a medical bill, an urgent car or home repair — things that are unexpected, necessary and urgent. A holiday and a new phone are none of those; save for those separately.

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