Rex says
Money math without the spreadsheet headache. Plug in your numbers and I'll show you exactly where the dollars land.
Try a scenario
Click to load — tweak from there.Inputs
Result
Emergency fund target
$15,560
Months of cover recommended
4
Essential spending per month
$3,890
Still to save
$12,060
Monthly contribution to close it
$1,005
Months your current cash covers
1
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Got your number — what next?
Pick one, it takes 20 secondsHow to use this
- 1Enter housing (rent/mortgage) ($/mo).
- 2Enter food & household ($/mo).
- 3Enter utilities & connectivity ($/mo).
- 4Enter insurance & healthcare ($/mo).
- 5Enter transport ($/mo).
- 6Enter minimum debt payments ($/mo).
- 7Enter income stability.
- 8Enter income earners in household (people).
- 9Enter dependants (people).
- 10Enter cash already set aside ($).
- 11Enter months to reach the target (months).
- 12Read your emergency fund target on the right — it updates as you type.
- 13Hit Share to keep the scenario or send it to someone.
About this calculator
The 'three to six months' rule is a starting point, not an answer — the right buffer depends on what your essential outgoings actually are and how quickly your income could be replaced. This calculator sizes the fund off essential spending only (housing, food, utilities, insurance, minimum debt payments, transport), then adjusts the month count for income volatility, number of earners, and dependants. It also returns how long your current savings would actually last and the monthly contribution needed to close the gap on your chosen timeline.
Worked example
Using the values the calculator loads with:
Inputs
- Housing (rent/mortgage): 1900 $/mo
- Food & household: 650 $/mo
- Utilities & connectivity: 280 $/mo
- Insurance & healthcare: 420 $/mo
- Transport: 340 $/mo
- Minimum debt payments: 300 $/mo
- Income stability: Salaried, ordinary risk
- Income earners in household: 1 people
- Dependants: 0 people
- Cash already set aside: 3500 $
- Months to reach the target: 12 months
Results
- Emergency fund target: $15,560.00
- Months of cover recommended: 4
- Essential spending per month: $3,890.00
- Still to save: $12,060.00
- Monthly contribution to close it: $1,005.00
- Months your current cash covers: 0.9
What each field means
Inputs
- Housing (rent/mortgage) ($/mo)
- The housing (rent/mortgage) used in the calculation, measured in $/mo. Starts at 1900 $/mo so you have a working example on load.
- Food & household ($/mo)
- The food & household used in the calculation, measured in $/mo. Starts at 650 $/mo so you have a working example on load.
- Utilities & connectivity ($/mo)
- The utilities & connectivity used in the calculation, measured in $/mo. Starts at 280 $/mo so you have a working example on load.
- Insurance & healthcare ($/mo)
- The insurance & healthcare used in the calculation, measured in $/mo. Starts at 420 $/mo so you have a working example on load.
- Transport ($/mo)
- The transport used in the calculation, measured in $/mo. Starts at 340 $/mo so you have a working example on load.
- Minimum debt payments ($/mo)
- The minimum debt payments used in the calculation, measured in $/mo. Starts at 300 $/mo so you have a working example on load.
- Income stability
- Pick the option that matches your situation — the maths changes per option. Choices: Very stable (tenured/public), Salaried, ordinary risk, Commission or bonus-heavy, Freelance / self-employed.
- Income earners in household (people)
- The income earners in household used in the calculation, measured in people. Starts at 1 people so you have a working example on load. Accepted range: 1–3 people.
- Dependants (people)
- The dependants used in the calculation, measured in people. Starts at 0 people so you have a working example on load.
- Cash already set aside ($)
- The cash already set aside used in the calculation, measured in $. Starts at 3500 $ so you have a working example on load.
- Months to reach the target (months)
- The months to reach the target used in the calculation, measured in months. Starts at 12 months so you have a working example on load.
Results
- Emergency fund target
- Returned as a money amount in US dollars and shown as the headline result. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Months of cover recommended
- Returned as a whole number. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Essential spending per month
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Still to save
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Monthly contribution to close it
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Months your current cash covers
- Returned as a whole number. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
FAQ
Should the target be based on income or spending?
Spending, and essential spending specifically. Income-based targets over-save for high earners with modest fixed costs and under-save for people whose fixed costs consume most of their pay. In an actual emergency you cut discretionary spending immediately — the fund only has to cover what you cannot cut.
Does a second earner really justify a month less?
It reduces the probability that household income goes to zero at once, which is the scenario the fund insures against. It does not help if both incomes come from the same employer or the same volatile sector — in that case treat the household as single-income.
Emergency fund or pay off debt first?
The common sequence is a small starter buffer of about one month of essentials, then attack high-interest debt, then finish the full fund. Without any buffer, the next unexpected bill goes straight back on the card you just paid down.
Where should the fund live?
In a separate, liquid, insured account you can reach within a day or two — a high-yield savings account is the standard choice. Separate from checking so it is not spent by accident, and not in investments whose value may be down at exactly the moment you need it.
Accuracy and limitations
- Results are estimates before tax, fees, and inflation unless an input explicitly covers them.
- Rates are treated as fixed for the whole period — variable-rate products will drift from this projection.
- This is educational maths, not financial advice. Check anything contractual with the lender or your accountant.
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Personal Financial Runway Calculator
How many months your savings cover you if income stops today.
Cite this calculator
Writing about this topic? Grab a citation — every link helps keep these tools free.
RevenueLab. (2026). Emergency Fund Target Calculator. Retrieved from https://www.revenuelab.fyi/toolbox/emergency-fund-target
<p>Source: <a href="https://www.revenuelab.fyi/toolbox/emergency-fund-target" target="_blank" rel="noopener">Emergency Fund Target Calculator — RevenueLab</a> (2026).</p>
Source: [Emergency Fund Target Calculator — RevenueLab](https://www.revenuelab.fyi/toolbox/emergency-fund-target) (2026).