Emergency fund calculator
Size an emergency fund, track current coverage, and project how long until you are fully funded.
Calculator personalLogic updated April 2026
This calculator sizes your emergency fund (monthly expenses × target months of cover) and projects how long it takes to fully fund it from your current savings, monthly contribution, and any interest earned along the way. The output tells you both the target dollar amount and the number of months until you reach it at your current rate.
How this is calculated
Formula
target = monthlyExpenses × targetMonths ; each month: balance += monthlyContribution + balance × monthlyRate ; loop until balance ≥ targetStep-by-step
- Multiply monthly expenses by the target months of cover (typically 3–6) to get the total emergency-fund target
- Start with your current savings as the running balance
- Each month, add your monthly contribution at the start of the month
- Apply monthly interest to the balance at the end of the month
- Continue until the balance reaches the target — that's the number of months to be fully funded
- Calculate months covered today (current balance ÷ monthly expenses) so you can see your existing buffer
- Rounding mode
- ROUND_HALF_UP
- Precision
- 20-digit internal precision (Decimal.js), rounded to 2 decimal places for display
- Logic last reviewed
Assumptions & limitations
What this calculator assumes
- Target amount equals monthly expenses multiplied by target months
- Contributions are made at the start of each month
- Monthly interest is applied to the balance
- Iteration is capped at 600 months
- Months covered = current balance divided by monthly expenses
What this calculator doesn’t account for
- Doesn't model lifestyle inflation that grows monthly expenses over time
- Doesn't account for tax on interest earned on the fund
- Doesn't simulate periodic withdrawals to handle real emergencies
- Doesn't factor in account fees that may apply to smaller balances
- Assumes a constant monthly contribution — variable income isn't modelled
Worked example
A household has $4,000 in savings, monthly expenses of $4,500, contributes $400/month toward the fund, earns 4% annually, and aims for 6 months of cover.
| Input | Value |
|---|---|
| Current savings | $4,000 |
| Monthly expenses | $4,500 |
| Target months | 6 |
| Monthly contribution | $400 |
| Annual rate | 4% |
Target: $27,000 — Months to fully funded: ~52 — Months covered today: 0.9
Target = $4,500 × 6 = $27,000. Starting from $4,000, the household needs another $23,000. At $400/month with light interest, the gap closes in about 52 months — under 4 and a half years. Today's balance only covers about 0.9 months of expenses, so the household has a long way to go but is on a clear schedule. Increasing contributions to $600/month would shorten the timeline to about 35 months.
Frequently asked questions
How many months of expenses should I save?
Most financial advisers recommend 3–6 months of essential expenses. Three months is appropriate for households with stable, dual incomes; six months suits single-income or self-employed households where income loss is more disruptive. Twelve months is reasonable for very risk-averse savers, freelancers, or those with health conditions that could limit working. The right number is the one that lets you sleep at night.
Where should I keep my emergency fund?
Somewhere accessible (24–48 hour withdrawal at most) and separate from your everyday transaction account. A high-interest savings account or money market account is ideal — interest offsets some of the inflation drag, and the friction of moving money to spending discourages dipping in for non-emergencies. Avoid term deposits; the lock-up defeats the purpose.
Can I invest my emergency fund?
Generally no — emergency funds need to be available the day you need them, and investments fluctuate. The typical risk is using the fund during a market crash (e.g., redundancy in a recession), which is exactly when invested funds are at their lowest. Once you have a fully-funded emergency cushion plus separate savings goals, then invested money can serve as a secondary buffer.
How do I rebuild after using it?
Treat rebuilding as a top-priority savings goal. Keep your emergency contribution at the same level (or higher) until the fund is back to target — every other discretionary spend can wait. Many households also pause investing temporarily to refill the emergency fund quickly. The earlier you rebuild, the smaller the window during which you're exposed to a second emergency.
Should I count my line of credit as an emergency buffer?
No. Credit lines depend on the lender's willingness to extend credit, which can be withdrawn precisely when you need it most (e.g., during job loss when your credit profile drops). They're a backup to a real cash emergency fund, not a replacement. The cash fund covers immediate, unconditional access; credit covers extended emergencies after the cash runs out.
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