Having turned 55, I can start collecting a $650-per-month pension from a former employer. But I don’t need the money now and can get $1,210 a month by waiting to age 62 to start taking benefits, or $1,613 if I wait until 65. Which option is best?

Without more details, it’s hard to say for sure. Indeed, it might well pay to hire a financial adviser to work it out, and I’ll suggest how in a moment.

But here are the basics:

This type of pension is typically based on the employer’s assumptions about the employee’s life expectancy. If you live to the expected age, the cost to the employer might be about the same no matter which option you choose.

Obviously, that’s because you’ll receive a bigger payment if you start at 65, but you’ll get it for fewer years.

Clearly, if you die at 60, you’d be better off starting at 55 than waiting until later. At the other end of the spectrum, you might come out ahead by starting at 65 if you live longer than expected, since you’ll get the larger payment for long enough to more than make up for the late start.

Now let’s see what happens using your numbers.

Start taking $650 a month at 55 and you’d win if you die before age 71. By the end of your 70th year, you’d have received $117,000.

You’d have received $116,160 if you started getting $1,210 a month at 62 and $96,780 if you’d waited until 65 and received $1,613 a month.

If you live at least to 72 but not to 75, you’d do better starting at 62. Live to 75 or longer and you’d do better by waiting until at 65 to start.

The longer you live, the more that late start will pay off. By the end of your 85th year, for example, the ager-55 start would have earned you, $234,000, vs. $333,960 with the age-62 start and $387,120 with the age-65 start.

But didn’t I say that if you lived to the expected age, each option would cost the employer the same?

Yes, I did. The employer probably assumes that money you do not receive is invested. If you start at 65 instead of 55, the employer has 10 years of investment earnings to help meet the larger monthly payments you’d receive.

In fact, you should consider this as well, though it makes the calculations much more complex.

Imagine that you earned 8 percent a year and started getting $650 a month at 55. You’d have about $75,000 at 62, compared to about $55,000 if you’d just collected the money and earned nothing on it. Because of this bigger head start, the start-after-55 option would beat the other options until you were about 85.

At that point — assuming you’d spent nothing, paid no tax and earned 8 percent a year — each option would earn you a nest egg of about $955,000.

Of course, it’s much more likely you will spend your pension and be taxed. And who knows what the investment return will be?

The point is, you could do quite well by starting your pension at 55, even though the monthly payment would be much smaller.

There are lots of other things to consider: Will the pension grow to offset inflation? What benefit will your spouse get after you die? How will taking the pension at a young age affect your taxes? Do people in your family tend to die young or keep on ticking?

Your benefits folks at work should be able to help with some of this. But, since there’s big money at stake, it might pay to hire an objective financial adviser to see how each option would fit into your overall retirement-funding picture.

I favor the “fee-only” advisers who charge an hourly or flat rate for advice and don’t sell products or execute trades.

The National Association of Personal Financial Advisors has a referral service for fee-only professionals at www.napfa.org. Or call (800) 366-2732.