Calculator
HYSA Emergency Fund Calculator
“Three to six months of expenses” is only as good as the expense list behind it, and most people never write that list down. List your actual essentials, pick how many months you want covered, and this multiplies out your real target — then simulates a HYSA balance growing from what you've saved plus what you add each month, with interest compounding on top, to show exactly when you get there.
Your emergency fund plan
List your essential expenses below, then press Calculate to see your plan.
Essential monthly expenses
Only what you'd still have to pay with no income coming in — rent, groceries, insurance, minimum debt payments — not everything in your budget. Skip anything you'd cut first, like subscriptions or dining out.
Press Fill common expenses for a starting list of what most U.S. households pay every month. Every amount is left blank on purpose — put in your own number, not a guess.
How long to cover
How many months you want to be able to live on this fund alone. Three months is the usual floor for a stable dual-income household; six to nine is more common for a single income or variable pay; a year or more for freelance or commission-based work.
Use it wisely: this multiplies your essentials directly, so it is the single biggest lever on your target.
Funding this from a HYSA
What you already have saved, what you can add every month, and the HYSA's advertised APY — held constant for the whole projection, the most favorable assumption possible since real HYSA rates float.
Use it wisely: raising the monthly amount shortens the timeline far more than chasing a slightly higher APY does.
For educational purposes only. Results are estimates and do not constitute financial, tax, or legal advice. Consult a qualified professional before making any financial decisions.
How to use it
List what you'd still owe every month with no income coming in — press Fill common expenses for a starting list, then put in your own numbers. Pick how many months you want covered, and enter what you've already saved, what you can add monthly, and your HYSA's APY.
Press Calculate for your plan, or flip on Real-Time Calculation to have it update as you type. Hover the ? beside any section for what it does and how to use it wisely.
Try raising the monthly amount by $50: the drop in the timeline is usually far larger than a slightly higher APY would give you.
Assumptions
- The target is your own essential expenses times your chosen coverage length — not a generic 3-to-6-month rule applied to your whole budget.
- The APY is held constant for the whole projection, the most favorable assumption possible since real HYSA rates float with the market.
- Interest compounds monthly on the balance already there, then that month's contribution is added on top.
- Assumes the contribution and the rate stay constant for the whole timeline, with no withdrawals along the way.