Dear Savvy Senior:

Is there an easy way to figure out how much I will need to save for retirement? My wife and I are both in our late 50s and want to figure out about how much we’ll need in order to retire comfortably. — Ready to Retire

Dear Ready: How much money you need to retire comfortably is a great question that all working adults should ask themselves. Unfortunately, far too few ever bother thinking about it.

But calculating an approximate number of how much you’ll need to have saved for retirement is actually pretty easy and doesn’t take long to do. It’s a simple, three-step process that includes estimating your future living expenses, tallying up your retirement income and calculating the difference.

Estimate living expenses

The first step — estimating your future retirement living expenses — is the most difficult. If you want a quick ballpark estimate, figure around 75% to 85% of your current gross income. That’s what most people find they need to maintain their current lifestyle in retirement.

If you want a more precise estimate, track your current living expenses on a worksheet and deduct any costs you expect to go away or decline when you retire, and add whatever new ones you anticipate.

Costs you can scratch off your list include work- related expenses such as commuting or lunches out, as well as the amount you’re socking away for retirement. You may also be able to deduct your mortgage if you expect to have it paid off by retirement, and your kid’s college expenses. Your income taxes should also be less.

On the other hand, some costs will probably go up when you retire, like health care, and depending on your interests, you might spend a lot more on travel, golf or other hobbies. And if you’re going to be retired for 20 or 30 years, you also need to factor in some occasional big budget items such as a new roof, heating/air conditioning system or vehicle.

Tally retirement income

Step two is to calculate your retirement income. If you and/or your wife contribute to Social Security, go to SSA.gov/MyAccount to get your personalized statement that estimates what your retirement benefits will be at age 62, full retirement age and when you turn 70.

In addition to Social Security, if you or your wife has a traditional pension plan from an employer, find out from the plan administrator how much you are likely to get when you retire. And figure in any other income from other sources you expect to have, such as rental properties, part-time work, etc.

Calculate the difference

The final step is to do the calculations. Subtract your annual living expenses from your annual retirement income. If your income alone can cover your bills, you’re all set. If not, you’ll need to tap your savings, including your 401(k) plans, IRAs or other investments, to make up the difference.

So let’s say, for example, you need about $60,000 a year to meet your living and retirement expenses and pay taxes, and you and your wife expect to receive $35,000 a year from Social Security and other income. That leaves a $25,000 shortfall that you’ll need to pull from your nest egg each year.

Then, depending on what age you want to retire at, you need to multiply your shortfall by at least 25 if you want to retire at 60, 20 to retire at 65, and 17 to retire at 70 — in this case, that would equate to $625,000, $500,000 and $425,000, respectively.

Why 25, 20 and 17? Because that would allow you to pull 4% a year from your savings, which is a safe withdrawal strategy that in most cases will let your money last as long as you do.

Jim Miller is a contributor to NBC-TV’s “Today” program and author of “The Savvy Senior.” Send your questions to Savvy Senior, P.O. Box 5443, Norman, OK 73070; or visit savvysenior.org.