Get These 3 Variables Right and Retire Earlier

How do you know if you can retire? Despite all the attention given to your retirement "number"—your total savings—there are several other important variables that go into the retirement equation. If you want an accurate estimate for when you could retire, you must choose reasonable values for each one of them. Get these numbers wrong, either too optimistic or too pessimistic, and it could throw off your retirement calculations by years.

In my experience, people tend to be overly pessimistic about their retirement variables. Maybe it's all the "bad" news about retirement. Or maybe it's an abundance of caution around this critical life decision. But if you can be realistic about these numbers without being reckless, you can potentially accelerate your retirement and the freedom it brings.

Even if you have a financial adviser, it's a good idea to become familiar with the key retirement variables yourself. Yes, some math is required, but it's pretty simple. And there are easy-to-use retirement calculators that can handle the details for you. So let's take a look at these important retirement parameters.

1. Living expenses. It's common to assume that your retirement living expenses will be a fixed percent of your pre-retirement income. But if your lifestyle is unique in any way, especially if you’re a diligent saver, these income-based estimates can be wildly inaccurate. The best way to know your expenses is to actually track them yourself. One expert says you can retire on less than 60% of your working income, which is consistent with my personal experience.

And the news about expenses gets better: The typical retirement calculation automatically increases your living expenses every year by the rate of inflation. That sounds reasonable at first glance. Yet research shows that most people’s expenses decline as they age. Studies show decreases from 16% to as much as 40% over the stages of retirement. Even with higher health-care costs, you simply can’t consume as much at 80 as you did at 60.

2. Inflation rate. Inflation remains a critical retirement variable, because it can influence your fixed living expenses and the real returns on your investments. Many fear higher inflation in the future. Pundits have been expecting it for more than a decade. Although conditions might favor higher inflation down the road, nobody knows for sure when or how it will arrive. In my opinion, trying to plan for extreme inflation is not sensible. And many retirees, myself included, experience a personal inflation rate that is below the government's official rate, proving that you have some control over how inflation impacts your life.

3. Tax rate. Taxes are one of the most feared and loathed factors in retirement. Yet in my experience as a middle-income retiree, taxes aren't as big a deal as they are made out to be by those with an agenda for your money (or your vote). In the lower tax brackets, income taxes are just another expense, and not a particularly large one. When calculating taxes for retirement, be especially careful to distinguish between effective and marginal tax rates. Your effective tax rate is your total tax divided by your income. Your marginal rate is the amount of tax you pay on your last dollar of income. That's a function of your tax bracket and is nearly always much higher than your effective rate.

Most retirement calculators use an effective rate, but that isn't always clear. If you mistakenly enter a marginal rate into a retirement calculator, you will grossly overestimate your tax liability and underestimate your available retirement income. For example, my marginal tax rate in my peak earning years was 28%; now that I'm retired, my effective tax rate has been around 6%. Big difference!

So there is room for optimism on some key retirement variables. But retirement planning is an exercise in reality, and the reality of the stock and bond markets right now is more negative than positive. Investment returns are one retirement variable where you cannot afford to be overly optimistic, or you could run out of money in your later years. Many experts point to current low interest rates and high market valuations as indicators that we must plan for lower returns going forward. How much should you scale back your expectations? That's anybody's guess, but I'm seeing estimates of from 2%-4% below the long term averages for stock returns.

Retirement analysis can be difficult and perplexing. A good retirement calculator can condense all the variables into a single view of your financial trajectory. For the most accurate picture, choose realistic values. Don't lengthen your journey to retirement with excessive assumptions for living expenses, inflation, or tax rates. But don't get overly confident about investment returns, either. A realistic analysis will increase your odds of working and saving the right amount, before you make the leap to retirement.

Darrow Kirkpatrick is a software engineer and author who lived frugally, invested successfully, and retired in 2011 at age 50. He writes regularly about saving, investing and retiring on his blog CanIRetireYet.com.

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