How much money should you keep ready for emergencies?© Francesco Milanese/stock.adobe.com, © goku4501/stock.adobe.com, © zendograph/stock.adobe.com, © nata777_7/stock.adobe.com; Photo illustration Encyclopædia Britannica, IncBuild an emergency fund, they say. It’s one of the basic bits of personal finance advice almost every expert offers. But how much do you need in your emergency fund? As with all things personal finance, how much you should set aside for a rainy day is, well, personal.

　　The short answer is that you should keep as much as you might reasonably expect to need during a temporary loss of income or for a major unplanned expense. But because your emergency fund should be kept in an ultra-safe place such as a checking or savings account, it’s probably not going to be the highest-performing investment in your portfolio. So you might not want to over-fund your emergency savings.

　　In other words, when deciding on the size of an emergency fund, you should seek a balance between covering your risk and optimizing your return. One key to determining that balance is to calculate your emergency fund ratio. 

　　How much to save in your emergency fund: 3-6-9 ruleThe basic guideline for emergency funds is to set aside enough money to cover your expenses for three, six, or nine months, depending on your needs and financial situation. Think about how long you would have to live off your savings if you lost your job, suffered an illness, or experienced some other major financial event.

　　If you have a higher risk tolerance, you might feel comfortable with only three months of emergency savings. This might be especially true if you have other assets, like investments or equity in your home, that you could draw on after three months. On the other hand, if you’re concerned about a long-term loss of income or financial shock, and you don’t have a lot of other assets to tap, you might feel more comfortable saving up nine months’ worth of expenses.

　　The easiest way to determine how much you need is to figure out your monthly expenses and multiply that by how long you want to be able to cover your costs. Let’s say you decide you need six months’ worth of funds to feel comfortable. If your total expenses—including housing, groceries, insurance, and debt payments—amount to $3,000 a month, you would set a goal to save $18,000 in your emergency fund.

　　There’s one more factor when deciding whether you should target three, six, or nine months’ expenses. Consider how your average expenses are allocated between mandatory costs (rent or mortgage payments, insurance premiums, groceries, and other things you can’t avoid) and discretionary expenses (things you could live without or cut back on if required). If a high percentage of your expenses are discretionary, and you believe you’re disciplined enough to truly cut back if needed, a three-month fund might work for you. 

　　The emergency fund ratioFinancial planners often take a formal approach to determining how much you should hold in short-term, accessible savings. The emergency fund ratio is modeled after the liquidity ratios used by stock analysts to determine a company’s ability to pay its bills. This ratio can help you determine how prepared you are to deal with a financial shock to your household budget.

　　Add up your liquid assets. How much do you have in immediately available funds? This includes your checking and savings accounts, as well as taxable investment accounts that you can access with relative ease.Tally your monthly expenses. Do a deep dive into your monthly costs, separating the mandatory and discretionary items.  Divide your total liquid assets by your mandatory expenses. Once you know those numbers, do a little math to get your ratio. For example, if you have $6,000 in your emergency fund and your monthly expenses are $3,000, your emergency fund ratio is 2.0. On the other hand, if you only have $1,000 in your account with that level of spending, your emergency fund ratio is 0.33.The higher the ratio, the better you’re prepared to handle an emergency. Consider aiming for a ratio that equals the number of months of mandatory expenses you want your emergency fund to cover. If you want a three-month emergency fund, your ratio should be at least 3.0.

　　The 50-30-20 rule is a strategy for planning your budget around the things you need, some things you want, and financial goals for the future.Encyclopædia Britannica, Inc.Where to find emergency moneyIt can take time to build an emergency fund, so you should also understand how to access other assets to hold you over when you experience a financial shock. This is especially important because an unexpected expense may arise before you reach your emergency fund goal.

　　Take an inventory of other assets you can draw on in a financial pinch. They might not be part of your “official” emergency fund, but they might help you weather a financial storm:

　　Life insurance cash value. If you have life insurance, you might be able to take a loan against your cash value. You’ll need to repay this money later or it will reduce your death benefit, but it can be a way to access money if you need it.Retirement accounts. You can take out a loan against your 401(k) if your plan administrator allows it. Be sure to factor in the opportunity cost (that is, the returns that would be compounding if those funds were still in your retirement account). If you leave or lose your job, your 401(k) loan becomes immediately due. You could be levied taxes and penalties if you can’t repay the loan. However, you might also be able to take a hardship withdrawal from an IRA or 401(k) without penalty.Home equity. A home equity loan or line of credit can help you tap into the value of your house to get through a tough time. However, this should be a last resort. If you don’t make your payments, you could lose your home, resulting in an even bigger financial shock.The Bank of Mom & Dad. Borrowing from parents or other family members can be a great resource when you’re first starting out in the “real world.” When you’re in college or starting your first job, you may not have had time to build up an emergency fund or save for financial opportunities. But it’s not fun to be in debt to a family member, so proceed with caution.Learn what community resources are available locally. If you can get assistance with utilities, heating, and rent, that frees up cash for other expenses. Likewise, if you can receive food from a local pantry or other community-based program, you can reduce your need for groceries, making it easier to get through your emergency.

　　Finally, make a list of what you can cut first. Prioritize your expenses. If you run into trouble, what’s the first subscription you should cut from your budget? Look at how much you eat out or spend on entertainment. In a financial emergency, these are the first expenses to cut so that you aren’t drawing down your emergency assets as quickly.

　　What to do after reaching your emergency fund goalThere’s a good chance you’ll have to build your emergency fund a little bit at a time. If your goal is to set aside $18,000 in an emergency fund, figure out how much you can add each month. If the answer is $500, it will take you three years to fully fund your emergency savings. However, along the way, you’ll be building a fund you can draw on for car repairs, new appliances, or other emergencies.

　　When you get a windfall, such as a work bonus, gift, or tax refund, consider putting some of it into your emergency fund to pump it up faster. Also, consider putting secondary income toward your emergency savings goal.

　　Once you fill your emergency fund, you can divert the money you’ve been using to build your rainy-day savings to reach other financial goals. Boost what you’re contributing to retirement, or increase what you’re allocating to pay down debt. You can also increase your insurance deductibles to reduce your monthly premiums. With a fully stocked emergency fund, you can likely handle the higher out-of-pocket expenses that come with increased deductibles.

　　The bottom lineYour emergency fund is your lifeline in tough economic times. Add up your expenses and look at your available assets. Figure out how much peace of mind you need in the event of a major financial shock, and use that to guide your target for an emergency fund.

　　Predatory lenders and credit card companies market themselves as available-when-you-need-it emergency funds. But the interest rates they charge can turn your temporary need into a long-term debt trap from which it’s difficult to escape.