This is a guest post from Robert Brokamp of The Motley Fool. Robert is a Certified Financial Planner and the adviser for The Motley Fool’s Rule Your Retirement service. He contributes one new article to Get Rich Slowly every two weeks.

Permit me to introduce a new term into the financial planning lexicon: goals-based budgeting. (Well, a Google search turned up a few other instances of its use, but they’re on government websites, so no one has seen them.) I came up with the term after reading through the comments of my last article (“The High Cost of Modern Living”) and reading J.D.’s recent article about his entry into the Third Stage of personal finance, which he explained thusly:

I’ve paid off my debt, built a cash cushion in savings, and am maxing out my retirement accounts. And after doing all of these things, I have money left over to spend on comic books and travel.

In my previous article, I listed several items we spend our money on — for instance, cell phones, cable TV, chocolate-covered pork fat — that didn’t exist in the past, and suggested that the allure of these modern inventions may explain why some people haven’t saved enough for retirement.

A few readers rose to defend their expenditures, arguing that many modern devices and services save time, increase efficiency, and replace older/costlier/less-efficient Stuff. Those are all valid points…if those purchases are aligned with your financial goals, or you’re saving enough to meet your financial goals and have money left over to spend on thingamajigs, doohickeys, and whatchamaspankits. This is J.D.’s “third stage” — the point at which you can relax a little bit with your spending.

Which brings us to this reader comment appended to J.D.’s article:

Whenever I hear that someone is “maxing out retirement accounts”, a red flag goes up. Depending on how late in life you’re starting and how much it will take to sustain your lifestyle, “maxing out” may not be enough. I hope that instead you are looking at how much you’ll need to accumulate and feel you are on track with that.

A very important point, indeed. If the analysis cited in a recent Wall Street Journal article is to be believed, nearly three of five baby boomers will run out of money in retirement. These folks have been walloped by stinky stocks, evaporating home equity, and interest rates that pay no interest. But many of them just didn’t save enough. For all of them, saving more is the solution.

Running Your Retirement Numbers
How do you know if you’re saving enough for retirement, or any other money-reliant goal? The best (though still imperfect) way is to use some sort of financial calculator, be it online tool, software program, or spreadsheet. There are loads of these available. Do a Google search on “retirement calculator” and you get 84,700 hits. No, wait — that’s what you get when you search on “Goldman Sucks.”

Well, no matter; you don’t need to search for a retirement calculator because I’m going to point out a few in this post. In fact, I’ll walk you step-by-step through my favorite among The Motley Fool’s calculators. Click on “Retirement,” and then on “Am I saving enough? What can I change?” This calculator can handle all kinds of variables: Social Security, pensions (and whether they adjust for inflation), anticipated spending levels in retirement, and Roth and traditional retirement accounts.

So gather your retirement account statements, pull up the online calculator, and get ready to peer into your possible future.

Getting Cozy With the Calculator
This calculator has input boxes, most of which have been completed with default data. You can get rid of those by typing in your own numbers (or zero if that field doesn’t apply). Certain areas are accompanied by a question mark. Click on one, and you’ll get an explanation of the desired data. Now, let’s start entering.

  • Personal information. The first few fields are pretty self-explanatory. If you plan to work part-time in retirement, enter your expected income and how long you plan to work.
  • Social Security benefits. Yes, you will receive Social Security (a topic I will cover in my next post). If you’re 55 or older, assume you’ll receive your estimated benefits. If you’re younger, be conservative by assuming you’ll receive 25% to 75% of your projected benefits, depending on the margin of safety you want to build into your analysis. The calculator will estimate your benefit, though you can enter the amount you received from your most recent Social Security statement (which arrived in the mail a few months before your last birthday) or visit the official government Social Securituy calculator to get an estimate.
  • Pension or defined-benefit plan. Make sure to indicate if your benefit will increase with inflation. This is also where you’d enter the payments you’ll receive from any other source of lifelong income, such as from an immediate annuity, reverse mortgage, or trust.
  • Your projections. For inflation, enter a number between 3% and 4%. Yes, inflation may go nuts down the road, but it hasn’t happened yet. What’s more likely (nay, inevitable, in my opinion) is that tax rates will rise. Soon-to-be retirees can expect their tax rates to drop once they retire. However, for my analysis, I’m assuming that won’t happen to me (I don’t plan to retire for 30 years). As for your income, assume it will increase at the same rate as inflation, unless you’re on the proverbial fast track. Finally, unless you know the day you’re going to die, choose an age between 90 and 100, depending on your health and family history. (If you’re looking for an estimate of your life expectancy, visit LivingTo100.)
  • Your projected monthly living expenses. The calculator allows you to break up your retirement spending in three phases. Generally, retirees spend more in their first five years as they enjoy their newfound freedom. Then, spending tends to decline in most categories (health care is the notable exception). Plug in the number in today’s dollars; the calculator will adjust for inflation. One big determinant of your retirement spending: Will your mortgage be paid off?
  • Your future, one-time investments. Expect an inheritance or to sell a business down the road? Enter those windfalls here. Just be realistic — many expected inheritances don’t materialize, often due to end-of-life medical expenses.
  • Your monthly savings (taxable accounts). This is where you enter the values and contribution amounts to non-retirement accounts, such as savings accounts and brokerage accounts that aren’t IRAs.
  • Your monthly savings (tax-advantaged accounts). Here’s where you input the values and contribution amounts to your retirement accounts. If you or your spouse has a 403(b), 457, or other defined-contribution plan, enter those values in the 401(k) fields. This is important: Enter future contributions to employer-sponsored retirement plans as a monthly amount, but enter future contributions to IRAs as an annual amount.
A note on returns: Be conservative when projecting investment returns. Young investors with stock-heavy portfolios shouldn’t assume more than 6%, and retirees with a mix of stocks and bonds should cap their assumed returns at 4%. I certainly hope that returns are higher, but I’m not betting my retirement on it.

And the Verdict Is…
It’s time to score your test. At the bottom of the page, click “get your results.” The analysis will be expressed in months, e.g., “Your living expenses after retirement will be fully funded for 173 months.” Divide that number by 12, and you’ll get how many years your savings will last.

If the calculator gives your retirement plan high marks, congratulations! If not, click on the “inputs” tab at the top and adjust the variables to see what combination of increased savings, reduced retirement income, and later retirement age will give your plan an acceptable score.

Don’t Take One Tool’s Word for It
While I think crunching your numbers is important, the truth is, the analysis will be wrong. There are just too many variables – such your rate of return, the rate of inflation, and how long you’ll live – that are unknowable. The best this tool will be able to do is give you a rough idea of whether you’re on track. Therefore, it’s important to do two things: 1) Run an analysis every year to see if you’re still on track, and 2) try other tools to get a second and third and fourth opinion. Here are a few others to consider:

If you’re looking for calculators that aren’t exclusive to retirement, head to Dinkytown (which, it should be noted, is not as fun as Funkytown).

Each calculator will give you a different result, due to how they run the numbers. You’ll be looking to see if a consensus emerges from the tools. If three of four calculators indicate that your retirement plan will succeed, then you’re probably on the right track. If three of four say you’ll run out of money, it’s time to plan to save more or work longer — or both. The same goes for your other financial goals.

Which brings us back to goals-based budgeting: If you’re saving enough for your priorities, then go nuts with the rest of your money. But I can tell you that there are millions of people in their 50s and older who wish they could turn back time and trade their purchases of yore for more savings today.

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