Pension Lump Sum Investment Calculator: Future Value of an Invested Payout
Work out what a pension lump-sum buyout could grow to if you take it and invest it — the key figure when deciding between a one-time lump sum and a lifetime monthly pension.
Adjust the inputs and select Calculate for a full breakdown.
Compare Common Scenarios
How the numbers shift across typical situations for this calculator:
| Scenario | Future value | Total growth |
|---|---|---|
| $120k · 6% · 15yr | $287,586.98 | $167,586.98 |
| $250k · 6% · 20yr | $801,783.87 | $551,783.87 |
| $80k · 5% · 10yr | $130,311.57 | $50,311.57 |
| $400k · 7% · 25yr | $2,170,973.06 | $1,770,973.06 |
How This Calculator Works
Enter the lump sum offered, the annual return you expect if you invest it, and the years until you'd start drawing on it. The calculator compounds the lump sum at that rate and shows the ending value and total growth. This is the 'invest the lump sum' side of the lump-sum-versus-monthly-pension decision.
The Formula
Future Value of a Lump Sum
PV = present value, r = annual rate, n = number of years
Worked Example
A $120,000 pension lump sum invested at 6% for 15 years grows to about $287,587 — more than doubling, with $167,587 of growth. But growth isn't the whole decision: a monthly pension is guaranteed income for life that you can't outlive, while an invested lump sum carries market risk and the responsibility to manage withdrawals. The right choice depends on the pension's payout rate, your other income, your health and longevity, and whether you value guaranteed income over control and potential growth.
Key Insight
The lump-sum-versus-pension choice is one of the most consequential retirement decisions, and this calculator only models one half — what the lump sum might become if invested. Weigh it against what the monthly pension is worth: divide the annual pension by the lump sum to get the implied payout rate; a high rate (say 7%+) is hard to beat safely and favors keeping the pension, while a low rate favors taking the lump sum. Other factors matter as much as the math: a pension is longevity insurance you can't outlive and isn't exposed to markets, but it usually dies with you (or a reduced survivor benefit), offers no flexibility, and depends on the plan's solvency (and PBGC limits). A lump sum gives control, potential growth, and a legacy for heirs, but shifts all the investment and longevity risk to you. Roll a lump sum directly into an IRA to avoid an immediate tax hit, and consider that the best answer is sometimes a blend — pension for baseline income, investments for the rest.
Frequently Asked Questions
How is the future value calculated?
The lump sum is multiplied by (1 + annual return) raised to the number of years. $120,000 at 6% for 15 years is $120,000 × 1.06¹⁵ ≈ $287,587.
Should I take the lump sum or the monthly pension?
It depends. Compute the pension's implied payout rate (annual pension ÷ lump sum): a high rate favors keeping the pension, a low rate favors the lump sum. Also weigh guaranteed lifetime income and plan solvency against control, growth potential, and leaving money to heirs. There's no universal right answer.
Is a pension lump sum taxable?
If paid directly to you, it's typically taxable as income that year — often a large hit. Rolling it directly into an IRA defers tax until you withdraw, which is why most people who take the lump sum roll it over rather than cashing out. Consult a tax professional before deciding.
What return should I assume?
Use a return matching how you'd actually invest a retirement lump sum — often a balanced figure (5% to 6%) rather than an aggressive one, since this money may be needed for income. Remember returns aren't guaranteed and this is nominal (before inflation), unlike a fixed pension which may or may not have a cost-of-living adjustment.
What are the risks of taking the lump sum?
You take on market risk (a downturn early in retirement can deplete it), longevity risk (you might outlive it), and the responsibility to manage withdrawals and avoid overspending or scams. A pension shifts those risks to the plan. The lump sum's advantages — control, growth, and a legacy — come with that added responsibility.
Related Calculators
Data Sources & Benchmarks
This calculator draws on 1 independent, dated source. The starting values for expected annual return are taken from the benchmarks below and refresh whenever the snapshots are updated.
Methodology & Review
Future value is the lump sum compounded at the annual return over the period. It assumes the lump sum is invested at once and left untouched at a constant return; it ignores withdrawals, fees, inflation, and tax on the rollover or on investment gains.
Written by Ugo Candido · Last updated May 22, 2026.