Instrument 05 · Protect
Emergency Fund Calculator Your Runway, In Months.
Your emergency fund runway is savings divided by essential monthly expenses: $9,000 against $3,000 of essentials is three months. Most guidance targets three to six months of essentials — six or more if your income is irregular, you are the only earner, or your job would take a long time to replace.
Runs in your browserNothing uploaded or storedLast reviewed
Cash and instant-access savings only. Not a pension, not equity, not a credit limit — a limit is somebody else's money and it disappears exactly when you need it.
Housing, utilities, food, transport, insurance, minimum debt payments. Not your normal spending — the floor you would drop to in a bad month.
Optional. This is what turns each rung below from a target into a date.
Three months is the common floor and six is the common target, but the right number is a function of how replaceable your income is. A salaried role in a deep market recovers faster than a single-client freelance business, and one earner in a household needs more cushion than two.
Enter your figures to see where you stand.
Runway is savings divided by one month of essentials. It assumes income stops entirely and spending drops to the floor you entered — a deliberately pessimistic reading, because that is the situation the fund is for.
Reading Your Result
What The Number Is Telling You.
- Under 1 month
- Exposed. Build a starter fund before anything else.
- 1–3 months
- A starter floor. Keep building while you clear expensive debt.
- 3–6 months
- The standard range for a stable income.
- 6 months or more
- Strong. Consider whether extra cash should now work elsewhere.
The Model
The Formula, In Full.
The arithmetic this instrument runs, with a worked example. Its test cases are published on the methodology page
Runway (months) = Savings ÷ Essential monthly costs
Target_k = k × Essential monthly costs
Months to target = (Target − Savings) ÷ Monthly contributionWorked example. Savings 9,000 ÷ essentials 3,000 = 3.0 months. Six months needs 18,000; at 500 a month that is 18 more months.
Assumptions and edge cases
- Only essential costs count — what you would still pay after losing your income.
- Savings means money you can reach within days without penalty.
- No interest is added; the runway is deliberately conservative.
| Edge case | Behaviour |
|---|---|
| Essentials zero | Em dash; no division. |
| Savings above target | Marked reached, with the surplus shown. |
| Contribution zero | Target date shows 'not at this pace'. |
Questions
Emergency Fund, Answered Plainly.
How much should I have in an emergency fund?
Enough to cover your essential expenses for three to six months. Essentials are what you would still have to pay with no income: housing, utilities, food, insurance, transport and minimum debt payments. Aim for the upper end, or beyond it, if your income is irregular, you support others, or your work would take a long time to replace. A starter fund of one month is the first milestone.
Should my emergency fund cover 3 or 6 months?
Three months suits a stable salary, a household with two incomes, or a skill in high demand. Six months or more suits the self-employed, single-income households, commission-based pay and anyone in a slow-hiring field. The right figure is the one that covers the time it would realistically take to replace your income, which is why the calculator shows several targets side by side.
What counts as an essential expense?
An essential expense is one you cannot stop without serious consequences: rent or mortgage, utilities, basic groceries, insurance premiums, transport you need, medication and minimum debt payments. Dining out, subscriptions, travel and savings contributions are not essential in an emergency — you would pause them. Counting only essentials keeps the target realistic and makes the runway figure honest.
Where should I keep my emergency fund?
Somewhere safe, separate and reachable within days: an instant-access savings account covered by your country's deposit protection is the usual choice. It should not sit in shares or other investments that can fall in value exactly when you need them, and it should not sit in your everyday account, where it quietly becomes spending money.
Should I build an emergency fund or pay off debt first?
A common sequence is a small starter fund first, then aggressive payoff of high-interest debt, then the full fund. Without any buffer, the next surprise expense goes back onto the card you are paying down. Once a starter fund exists, every spare unit usually does more against a high interest rate than in savings. The debt payoff calculator shows how fast that goes.
What counts as an emergency?
An emergency is unexpected, necessary and urgent: losing your income, a medical bill, an essential car or home repair. A sale, a holiday or a predictable annual bill is not an emergency — those belong in sinking funds so they never touch the emergency fund. Keeping the definition strict is what keeps the fund there when it is really needed.
How can I build an emergency fund faster?
Automate it, feed it windfalls and redirect money you free up. A fixed transfer on payday means saving happens before spending; tax refunds and bonuses can go straight in; cancelled subscriptions are the quickest source of freed-up money. Build a one-month starter fund first so progress is visible, then grow it steadily. The savings goal calculator turns any target and date into a monthly figure.