One solution is to use an online tool designed for the job, such as the AARP Retirement Calculator at aarp.org/calculators. But if you’re in a rush, you might try one of these three common rules of thumb for a rough estimate of your needs and resources—emphasis on “rough.” Each can give you a snapshot of where you stand and motivate you to dive deeper into retirement planning.

One approach is to target a multiple of your salary. T. Rowe Price, for example, suggests a wide range for savings at 65: from seven times your annual gross income for lower-income retirees to 13½ times income for high earners. A dual-income household making $75,000 at age 65, by the company’s calculation, should have about eight times that amount saved, or $600,000. Fidelity says to aim to have six times your salary in retirement savings by age 50 and 10 times your salary at age 67.

The reasoning: T. Rowe Price’s range of multiples is so wide because Social Security has different impacts at different income levels. For someone who was earning $15,000 a year, benefits replace about 75 percent of income, according to a 2022 Social Security Administration study. But for someone who was making $150,000 a year, benefits replace only about 27 percent of income.

The caveat: A salary multiple is just a ballpark estimate, says Roger Young, a thought leadership director at T. Rowe Price. “It doesn’t provide a one-size-fits-all answer,” he says. “The rule of thumb is most helpful for people who are a ways from retirement to provide a general sense if they are on track.”

This method involves figuring out how much income you will want to draw from your investments each year, then multiplying that number by 25 to determine how big your nest egg should be upon retirement. Consider, for example, a two-earner household, each person due to collect the current average monthly Social Security retiree benefit of $1,830, for a total of about $44,000. If their budget requires drawing an additional $20,000 a year from retirement savings to maintain their lifestyle, they’d have a savings target of 25 times $20,000, or $500,000.

The reasoning: The assumption is that you will withdraw 4 percent of your savings for income in your first year of retirement, then adjust that amount to account for inflation in each of the following years. That 4 percent withdrawal rate is a rule of thumb in itself: In the 1990s, California financial adviser William Bengen found that based on diversified stock and bond portfolio returns from 1926 to 1976, assets would last for at least 30 years if investors stuck to this 4 percent withdrawal rate.

The caveat: “The 4 percent rule works based on historical performance in many scenarios,” says Randy Hallier, a financial planner at Creative Planning in St. Petersburg, Florida. “But for investors who retire and start taking their withdrawals when the market is down or flat, the math is very different. Their portfolios lose value early on, and there’s less to stretch over a retirement.”

Another shortcoming of the rule is its assumption of a 30-year time horizon, which may not be long enough, says Renee Hanson, an adviser at Affinity Wealth Advisory Group in Phoenix. People estimate their life expectancy based on averages, she says, “but you have to figure you’re going to live well beyond that when planning for making your money last.”

This target: Save enough that you’ll be able to replace, with Social Security and any pension income, 70 percent to 80 percent of your annual preretirement income. Our hypothetical couple earning $75,000 a year, then, would aim for income ranging from about $53,000 to $60,000. That would mean somewhere between $9,000 and $16,000 in income along with Social Security, requiring roughly $225,000 to $400,000 in retirement savings.

The reasoning: Once you retire, certain expenses will either decline or go away, so it will take less money to support your lifestyle. For example, you will no longer have to carve out some of your income for retirement savings.

The caveat: Many people have unrealistic expectations about how far their expenses will decline in retirement, Hanson says. “I have yet to see someone retire and suddenly spend a lot less,” she says. “They may spend less on some things but spend more on hobbies, travel, eating out and services that are hard to do yourself, such as yard work. And, of course, medical care costs are likely to go up, too.”

After an initial burst, spending typically declines. A recent study by the Rand Corp. found that after age 65, spending falls steadily at all wealth levels by an average 1.7 percent annually for singles and 2.4 percent a year for couples.