Lump Sum For Annuity Income
Calculator

Inputs

Required lump sum
568,357.448924

Results

Required lump sum
568,357.448924
Total paid out
900,000
Interest earned over the payout
331,642.551075

Retirement planning results

Required lump sum568,357.448924
Total paid out900,000
Interest earned over the payout331,642.551075

formula-map diagram

Required lump sum
568,357.448924
Total paid out
900,000
Interest earned over the payout
331,642.551075

Retirement planning relationship

Formula

L = PMT × (1 - (1 + i)^-n) ÷ i

= 568357.44892448

Note

This is not financial advice. It is a simplified model: it applies the displayed standard formula to the figures you entered, assumes a single constant rate for every year, and ignores taxes, fees, sequence-of-returns risk, health costs, longevity risk and any country's specific pension, benefit or minimum-distribution rules. Real returns can be negative and real retirements rarely follow a smooth curve. Check the assumptions and consult a licensed adviser before acting on any figure.

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Frequently asked questions

What does this calculator find?+

It's the reverse of an annuity income calculation: given a target periodic income, an interest rate, and a payout duration, it works out the lump sum of capital needed today to fund that income stream. It answers 'how much do I need to deposit to get this monthly amount?'

Why does the required lump sum shrink with a higher assumed interest rate?+

A higher interest rate means the capital itself earns more between payments, so less principal is needed upfront to sustain the same income level — the growth does more of the funding work.

Does a longer payout period always require more capital?+

Generally yes for a fixed periodic amount, since more total payments must be funded, but the relationship isn't strictly linear because compounding also has more time to help fund later payments — the net effect still increases the lump sum needed for longer terms.

Should I use a nominal or real (inflation-adjusted) interest rate?+

If your target income needs to keep its purchasing power over time, use a real rate (net of expected inflation) or build in periodic increases; using a nominal rate without adjusting the income will understate how much capital you truly need for a flat real income.

Is this the same as a bank CD or GIC calculation?+

It's similar in structure (both use time-value-of-money math), but a CD/GIC typically returns interest without depleting principal, while an annuity-style calculation here assumes the balance is drawn down to zero (or near it) by the end of the term, which supports a larger payment for the same lump sum.