Pension Lump Sum vs Annuity: How to Calculate Which Is Worth More

The Decision Most Retirees Get Wrong

Pension administrators present the lump sum and annuity options side by side. The lump sum number is large. It looks like freedom. Most people take it without calculating whether it actually pays more over their lifetime.

That instinct is expensive.

The annuity option is, mathematically, a longevity insurance product. The pension fund pools mortality risk across thousands of participants. An individual investor cannot replicate that pricing. If you live past the breakeven age, the annuity almost always wins on total dollars received.

The correct framework is not "which number looks bigger." It is "what rate of return does the lump sum need to generate in order to match the annuity's lifetime payout." Once you know that implied rate, the decision becomes straightforward.

How the Implied Rate of Return Calculation Works

The implied rate is the internal rate of return (IRR) you would need to earn on the lump sum to produce the same after-tax income stream as the annuity, over your projected lifespan.

Here is the formula structure:

1. Take the annual annuity payment.
2. Multiply by your projected years in retirement.
3. That total is the annuity's gross lifetime payout.
4. Set the lump sum as the present value.
5. Solve for the discount rate that equates the two streams.

Most spreadsheet tools solve this with an IRR or RATE function. CalcMoney's retirement calculator handles it directly. But the math is accessible enough to run manually for a first-pass check.

Example 1: The Engineer Who Nearly Left $218,000 Behind

A 62-year-old engineer retiring from a state government position receives two options.

• Lump sum: $485,000
• Single-life annuity: $2,850 per month ($34,200 per year)

She expects to live to age 84. That gives her 22 years of payments.

Total annuity payout over 22 years: $34,200 x 22 = $752,400.

Using a present value calculation with the $485,000 lump sum and $34,200 annual payments over 22 years, the implied rate of return is approximately 5.87% per year.

That is the rate her reinvested lump sum must earn, after taxes and fees, every year for 22 years to match the annuity.

She holds a moderate-risk portfolio. Her realistic after-tax return expectation is 5.1% annually. The annuity wins. Over 22 years, she collects $752,400 in annuity income. Her reinvested lump sum at 5.1% grows to approximately $534,000 in nominal terms, but to generate $34,200 per year she would deplete the principal entirely by age 82. Two years before she expected to die, the account would reach zero.

The annuity puts $218,000 more in her pocket over the same period, with no depletion risk.

Example 2: The Executive With a Different Profile

A 60-year-old corporate executive receives the following from a frozen defined-benefit plan.

• Lump sum: $1,240,000
• Single-life annuity: $5,600 per month ($67,200 per year)

He projects living to age 80. That gives him 20 years of payments.

Total annuity payout: $67,200 x 20 = $1,344,000.

Implied rate of return on the lump sum over 20 years: approximately 3.94% per year.

He manages a diversified portfolio with a 15-year track record averaging 7.2% annually after fees. His marginal tax rate is 37%. His after-tax investment return is approximately 6.1%.

At 6.1% annual growth, his $1,240,000 lump sum compounds to approximately $4,000,000 over 20 years if he reinvests returns. Even withdrawing $67,200 per year, he retains a residual balance of approximately $2,100,000 at age 80. That balance transfers to his estate. The annuity pays nothing after his death.

The lump sum wins here by a substantial margin, and it wins on two fronts: higher income-equivalent returns and a meaningful estate value.

The Five Variables That Shift the Answer

1. Your Realistic After-Tax Investment Return

This is the most abused variable in the analysis. People use pre-tax returns, gross of fees, from exceptional market periods. Use your actual after-fee, after-tax compound annual return from the last 10 years. If you do not have that figure, use 4.5% for a balanced portfolio as a conservative baseline.

2. Life Expectancy

The Social Security Administration's actuarial tables show a 62-year-old woman has a 50% probability of living past age 86.6. A 62-year-old man has a 50% probability of living past age 84.1. These are medians. If your family history, health status, or lifestyle suggests you are above-median longevity, extend your projection by five years. The annuity's advantage grows materially with each additional year.

3. Spousal Survivor Benefits

A single-life annuity pays more per month. A joint-and-survivor annuity reduces monthly payments by 10% to 30% to cover a spouse after the primary annuitant's death. Evaluate whether your spouse has independent income. If not, the reduction in monthly payment is worth the protection. Never assume the single-life option is better simply because the monthly number is larger.

4. Pension Fund Solvency

Private-sector pensions carry credit risk. The Pension Benefit Guaranty Corporation (PBGC) insures single-employer plans up to $7,142.88 per month in 2025 for retirees at age 65. If your monthly annuity exceeds that cap, the lump sum eliminates counterparty risk entirely. Public-sector pensions carry different risk profiles depending on state funding ratios. Check your plan's most recent funded status disclosure.

5. Inflation Adjustment

Most private pensions pay a fixed nominal annuity. At 3% annual inflation, a $34,200 payment in year one has the purchasing power of $18,940 by year 22. Lump sums invested in equities provide a natural inflation hedge. If your annuity has no cost-of-living adjustment, the lump sum gains a compounding advantage that the raw payment comparison does not capture.

The Breakeven Age: How to Find Yours

The breakeven age is the point at which cumulative annuity payments exceed the future value of the lump sum invested at your realistic return rate.

The formula is not complex. You need three inputs:

• The lump sum amount (L)
• The annual annuity payment (A)
• Your expected annual investment return (r)

At each year (t), compare:

• Cumulative annuity received: A x t
• Lump sum future value minus withdrawals: L x (1 + r)^t, with A withdrawn each year

The year those two values cross is your breakeven age. If your projected lifespan exceeds that age, the annuity wins on dollars. If it does not, the lump sum wins.

For most moderate-return investors, the breakeven falls between age 79 and 83. For high-return investors managing concentrated equity portfolios, it can extend to age 87 or beyond.

The Tax Dimension

Lump sum distributions from pensions roll into an IRA without tax consequence if executed as a direct rollover. Annuity payments are taxed as ordinary income in the year received. If your tax rate in retirement is lower than your current rate, that changes the net present value comparison. Model both streams on an after-tax basis. The pre-tax comparison routinely overstates the annuity's advantage for high earners who expect a significant tax rate reduction in retirement.

Making the Calculation Before the Deadline

Pension elections are irrevocable. You complete the paperwork once. There is no adjustment after the fact.

Before you sign anything, run the implied rate of return calculation. Compare it against your realistic after-tax investment return. Factor in your projected lifespan, your spouse's situation, and your pension fund's solvency rating.

These are not abstract variables. Each one shifts the outcome by tens of thousands of dollars.

CalcMoney's retirement calculator lets you input your specific lump sum and annuity figures, set your return assumptions, and see the breakeven age and lifetime dollar comparison side by side. The numbers take approximately three minutes to generate. The decision you are making will affect your income for the next 20 to 30 years.

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Run your pension comparison now and find your breakeven age →