Pension Lump Sum Calculator

Enter your plan's lump-sum offer and its monthly pension offer, and this calculator invests the lump sum to pay you the pension's own checks — showing whether it lasts to your planning age, what's left for heirs, and the return the pension is implicitly paying you.

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How the lump sum vs pension comparison works

The only honest way to compare a pile of money to a stream of checks is to make the pile do the stream's job. This calculator invests your lump sum at the return you expect and has it pay you the pension's own monthly check — same amount, same schedule, same cost-of-living increases if your pension has them. Then it asks the one question that matters: does the money last to your planning age, and is anything left over? If the lump sum can replicate every pension check and still leave a balance, the lump sum is winning on your assumptions. If it runs dry at 81 and the pension would have kept paying, the pension is quietly offering you a better return than you expected to earn — and the calculator tells you exactly what that implied return is, so you know the hurdle your investing has to clear.

The chart shows the lump sum's balance year by year while it pays out — a curve that either survives the whole horizon or bends to zero. Where it hits zero is the verdict.

The formula

balancenext month = (balance − pension check) × (1 + r ÷ 12)
implied return = the r where the balance hits exactly $0 at your planning age

Balance starts at the lump sum, the pension check is the monthly amount your plan offered (rising annually if it has a COLA), and r is your expected annual return, compounded monthly. The check is withdrawn at the start of each month and the remainder grows. The implied return is found by solving that recurrence for the break-even rate — it's the return your pension is effectively guaranteeing you over the horizon you chose, and it's the single most useful number on this page.

Worked example

A plan offers $400,000 as a lump sum or $2,400/month single-life starting at 65, no COLA. Planning to age 85 and expecting a 5% annual return:

The invested lump sum pays all 240 checks — $576,000, matching the pension dollar for dollar — and still holds $94,464.97 at age 85 for heirs or long-term care. The pension's implied return works out to 3.9%, so a 5% earner beats it.

Rerun it at a 2% return and the picture flips: the lump sum runs out at age 81 yrs 3 mo, having paid $468,076.70 — the pension pays 3 years 9 months longer and $107,923 more. Same offer, same person; the entire decision lives inside that return assumption.

The implied return is the real question

Ignore the size of the lump sum — it's designed to look impressive. The number that decides this is the implied return: what the pension effectively pays you for handing the money back. If your pension's implied return is 5.5% and you're honestly a balanced investor hoping for 6%, that pension is a guaranteed bond paying nearly your whole expected return with zero market risk and zero chance of outliving it — hard to beat. If the implied return is 3% and you have decades of horizon, the lump sum has a real case. And the horizon matters enormously: live five years past your planning age and the pension's implied return climbs, because those are checks the lump sum never had to fund.

What the math can't settle is the trade at the heart of it. A pension is longevity insurance — income you cannot outlive, immune to market crashes and to the version of you that panic-sells in a downturn; but a single-life pension usually dies with you. A lump sum is flexibility and legacy — heirs inherit what's left, you can spend unevenly, cover emergencies — but market risk and longevity risk are now yours alone. Two facts worth one line each: private pensions are insured by the federal PBGC up to legal limits, so "the company might fold" is a smaller risk than it feels; and most plans offer joint-and-survivor options that keep paying a spouse for a smaller check — not modeled here, but often the better pension to compare. A pension is a guarantee and a lump sum is a bet — this page shows the math, but survivor needs, taxes, and how you sleep at night are yours to weigh.

Frequently asked questions

Should I take the lump sum or monthly pension?

Compare the pension's implied return — the rate at which the invested lump sum could exactly replicate the pension's checks to your planning age — against what you can honestly earn. If the implied return is near or above your realistic expected return, the pension is a guaranteed deal you probably can't beat, with no market or longevity risk. If it's well below, the lump sum offers real upside plus flexibility and an inheritance. Health, a spouse who needs survivor income, and your appetite for managing money in your 80s all tilt the answer.

How do I compare a lump sum to a pension?

Make them do the same job: invest the lump sum and withdraw the exact monthly check the pension would pay, then see whether the money lasts to your planning age. If it lasts with money left over, the lump sum wins on your assumptions; if it runs out early, the pension wins. This apples-to-apples test is exactly what this calculator runs, month by month, including any cost-of-living increases your pension has.

What return would I need to beat my pension?

The calculator computes it for you: the implied return is the annual rate at which the lump sum funds every pension check and hits exactly zero at your planning age. Typical single-life offers imply somewhere around 4–6% to normal life expectancy, and the longer you live, the higher the bar climbs. Remember the pension delivers its rate guaranteed — beating it with investments means clearing the same hurdle after fees, in every market, for decades.

What happens to my pension when I die?

A single-life pension stops — no matter whether you collected two checks or two thousand. Most plans offer joint-and-survivor options that keep paying your spouse 50–100% of the benefit in exchange for a smaller monthly check, which is often the right comparison to run. A lump sum works the other way: whatever remains passes to your heirs, which is the strongest genuine argument for taking it.

Is the pension lump sum taxable?

Not immediately, if you move it correctly: a direct rollover into an IRA or your 401(k) defers all tax until you withdraw the money later. Take it as a check payable to you instead and the plan must withhold 20% for taxes, the full amount becomes taxable income that year, and a 10% early-withdrawal penalty can apply before age 59½. Almost everyone choosing the lump sum should use the direct rollover — talk to the plan administrator and a tax professional before signing anything.

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