An emergency fund has one job: be there when you need it. But a big pile in a 0.38% savings account loses ground to inflation. A simple ladder keeps some cash ready today and puts the rest where it earns more. Here is how to split it, using official Treasury and FDIC rates.
How big should your emergency fund be?
There is no perfect number, but these rules of thumb get most people close:
- Starter fund: $1,000 to $2,000, or one month of bare-bones expenses. Enough for a car repair or a vet bill without a credit card.
- Two-income household, steady jobs: 3 months of essential expenses (rent or mortgage, food, utilities, insurance, minimum debt payments).
- One income, self-employed, commission pay, or kids: 6 months.
- Job in a shaky industry, or close to retirement: 9 to 12 months.
Count essential expenses, not your whole budget. If you lost your job, you would cut dining out and streaming. A household spending $6,000 a month might only need $4,000 a month to get by, so a 3 to 4 month fund is about $12,000 to $16,000. That is where the $15,000 example below comes from.
When each option wins
| Option | Wins when | Loses when |
|---|---|---|
| High-yield savings | You might need the money this week. No waiting, no selling, insured by the FDIC. | Big balances sit for years. Even good online rates usually trail T-bills, and the national average is 0.38%. |
| T-bills | You can wait a few weeks or months. Higher rate today, and no state income tax on the interest. | You need cash the same day. Selling early at a broker takes a day or two and the price can move a little. |
| I bonds | Money you will not touch for at least a year. Rate rises with inflation, and the 1.40% fixed part lasts the life of the bond. | You may need it within 12 months. You cannot cash it at all in year one, and before 5 years you give up 3 months of interest. |
Rates today
| Option | Rate | How fast you get it | Source, as of |
|---|---|---|---|
| Savings account (national average) | 0.38% | Same day | FDIC, Oct 19, 2026 |
| Money market deposit account (avg.) | 0.63% | Same day | FDIC, Oct 19, 2026 |
| 4-week T-bill | 3.976% | 4 weeks, or sell early at a broker | Treasury auction, Oct 29, 2026 |
| 13-week T-bill | 4.138% | 13 weeks, or sell early at a broker | Treasury auction, Nov 2, 2026 |
| 26-week T-bill | 4.298% | 26 weeks, or sell early at a broker | Treasury auction, Nov 2, 2026 |
| I bond (bought Nov 2026–Apr 2027) | 5.51% (1.40% fixed) | Locked 12 months. Lose 3 months of interest if cashed before 5 years | TreasuryDirect, Nov 1, 2026 |
Savings rates are national averages, not one bank's offer. Many online banks pay more; check that a bank is FDIC insured. T-bills and I bonds are U.S. government securities, not FDIC-insured deposits.
A simple three-step ladder
- Step 1, ready cash (about 1 month of expenses): a high-yield savings account at an FDIC-insured bank. For a car repair this week.
- Step 2, short ladder (2–3 months): 4-, 13- and 26-week T-bills, set to roll over. One comes due every few weeks. Interest is free of state income tax.
- Step 3, slow money (the rest): I bonds, once you have held step 2 for a year. Up to $10,000 per person per year online. You cannot touch them for 12 months.
Example: a $15,000 emergency fund
| Bucket | Amount | Where |
|---|---|---|
| Ready cash | $5,000 | High-yield savings |
| Short ladder | $7,000 | T-bills: 4, 13 and 26 week |
| Slow money | $3,000 | I bonds |
Run your own numbers with the T-bill ladder tool and the T-bill calculator. Compare taxes in T-bill vs CD after tax. Saving for gifts instead? See where to park your holiday fund.
Liquidity, penalties and taxes in plain words
How fast can I get my money?
Savings: usually the same day, or next business day for a transfer to another bank. T-bills: on the due date the money lands in your account automatically. Need it sooner? At a brokerage you can sell before the due date, usually with cash in a business day or two. At TreasuryDirect you cannot sell early; you have to move the bill to a broker first, which is slow. That is one reason many people hold their T-bill ladder at a broker. I bonds: locked for the first 12 months, then cash out any time online.
Are there penalties?
Savings: none, though some banks limit how many withdrawals you make a month. T-bills: no penalty, but if rates rose since you bought, you may sell for a few dollars less than you paid. Hold to the due date and you get the full face value. I bonds: cash out between year 1 and year 5 and you lose the last 3 months of interest. After 5 years, no penalty.
How are they taxed?
Savings interest is taxed by the federal government and your state. T-bill interest is taxed federally but not by your state or city, which matters in high-tax states. I bond interest is also federal only, and you can wait to pay the tax until you cash the bond. If you use I bond money for qualified college costs, the interest may be tax-free; check the TreasuryDirect rules.
Ladder math: the $15,000 example, year one
Rough, before tax, using the rates in the table above. Real results depend on the rates when each bill rolls over and the I bond's inflation part, which resets every 6 months.
| Bucket | Amount | Rate used | About this much interest in a year |
|---|---|---|---|
| Ready cash (savings, national average) | $5,000 | 0.38% | $19 |
| 4-week T-bill | $2,000 | 3.976% | $80 |
| 13-week T-bill | $2,500 | 4.138% | $103 |
| 26-week T-bill | $2,500 | 4.298% | $107 |
| I bonds | $3,000 | 5.51% | $165 |
| Total ladder | $15,000 | About $474 | |
| Same $15,000 all in average savings | $15,000 | 0.38% | About $57 |
That is roughly $400 more a year for the same safety, plus a T-bill coming due every few weeks. A high-yield online savings account paying more than the national average shrinks the gap, so compare your bank's actual rate before you move anything.
How to set it up, step by step
- Add up one month of essential expenses. Multiply by 3, 6 or more using the rules above.
- Open or pick an FDIC-insured high-yield savings account and park one month there.
- At your broker (or TreasuryDirect), buy 4-, 13- and 26-week T-bills with the next 2 to 3 months, and turn on automatic rollover.
- After a year of building, move money you truly will not need for 12 months into I bonds, up to $10,000 per person per year.
- Check once a quarter. If you used the fund, refill the savings bucket first.
Track your ladder
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Questions and answers
Where should I keep my emergency fund?
Split it by how fast you might need it. Keep about one month of essential expenses in an FDIC-insured high-yield savings account for same-day access. Put the next 2 to 3 months in short T-bills that come due every few weeks. Money you will not need for at least a year can go into I bonds. This keeps you covered for a surprise bill and still earns more than one big savings balance.
Are T-bills good for an emergency fund?
Yes, for the part you will not need this week. A 13-week bill auctioned Nov 2, 2026 paid 4.138%, versus a 0.38% national savings average, and the interest is free of state income tax. Hold them at a broker so you can sell early if needed; you usually get cash in a business day or two, though the price can move a little if rates changed. Held to the due date, you get the full face value back.
Can I use I bonds for an emergency fund?
Only for money you will not need for at least a year. You cannot cash I bonds at all in the first 12 months, and if you cash them before 5 years you give up the last 3 months of interest. Think of them as the back of the ladder: the money behind your savings and T-bills. Each person can buy up to $10,000 a year online at TreasuryDirect.
What is the I bond rate now?
5.51% for I bonds bought Nov 1, 2026 through Apr 30, 2027, per TreasuryDirect. That is made of a 1.40% fixed rate, which stays with the bond for its whole life, plus an inflation part that resets every 6 months. So your rate after the first 6 months will change, but it can never go below zero.
Are T-bills FDIC insured?
No. T-bills are backed by the full faith and credit of the U.S. government, not by the FDIC. Bank savings and money market deposit accounts are FDIC insured up to $250,000 per depositor, per insured bank, per ownership category. If you hold T-bills at a broker, the broker account itself is a separate matter; the bills are still U.S. government debt held in your name.
How big should my emergency fund be?
A common rule is three to six months of essential expenses: housing, food, utilities, insurance and minimum debt payments. Lean toward 3 months with two steady incomes, 6 months with one income or self-employment, and more if your job is shaky. If that feels huge, start with $1,000 to $2,000 or one month in savings, then build the T-bill and I bond steps over time.
Sources: U.S. Treasury auction results; FDIC National Rates and Rate Caps; TreasuryDirect I bond rates. Rates as shown on the dates listed. Educational only, not investment advice.